Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

ablation In medicine, the removal or destruction of a body part or tissue or its function. Ablation may be performed by surgery, hormones, drugs, radiofrequency, heat, or other methods.

abscess An enclosed collection of pus in tissues, organs, or confined spaces in the body. An abscess is a sign of infection and is usually swollen and inflamed.

acute Symptoms or signs that begin and worsen quickly; not chronic.

acute lymphoblastic leukemia (lim-fo-BLAST-ik loo-KEE-mee-a) ALL. A quickly progressing disease in which too many immature white blood cells (called lymphoblasts) are found in the blood and bone marrow. Also called acute lymphocytic leukemia.

acute lymphocytic leukemia (lim-fo-SIT-ik loo-KEE-mee-a) ALL. A quickly progressing disease in which too many immature white blood cells (called lymphoblasts) are found in the blood and bone marrow. Also called acute lymphoblastic leukemia.

acute myelogenous leukemia (mye-eh-LAH-jen-us loo-KEE-mee-a) AML. A quickly progressing disease in which too many immature white blood cells (not lymphocytes) are found in the blood and bone marrow. Also called acute myeloid leukemia or acute nonlymphocytic leukemia.

adjunct agent In cancer therapy, a drug or substance used in addition to the primary therapy.

adjunctive therapy Another treatment used together with the primary treatment. Its purpose is to assist the primary treatment.

adjuvant therapy (AD-joo-vant) Treatment given after the primary treatment to increase the chances of a cure. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, or biological therapy.

adverse effect An unwanted side effect of treatment.

aggressive A quickly growing cancer.

AJCC staging system A system developed by the American Joint Committee on Cancer for describing the extent of cancer in a patient’s body. The descriptions include TNM: T describes the size of the tumor and if it has invaded nearby tissue, N describes any lymph nodes that are involved, and M describes metastasis (spread of cancer from one body part to another).

alkaloid A member of a large group of chemicals that are made by plants and have nitrogen in them.

alkylating agent A drug that is used in the treatment of cancer. It interferes with the cell's DNA and inhibits cell growth.

all-trans retinoic acid A form of vitamin A that is used in the treatment of acne. It is also being studied in cancer prevention and as a treatment for acute promyelocytic leukemia, usually in combination with other drugs. Also called tretinoin.

allogeneic (Al-o-jen-AY-ik) Taken from different individuals of the same species. Also called allogenic.

allogeneic bone marrow transplantation (AL-o-jen-AY-ik) A procedure in which a person receives stem cells (cells from which all blood cells develop) from a genetically similar, but not identical, donor.

allogeneic stem cell transplantation (AL-o-jen-AY-ik) A procedure in which a person receives stem cells (cells from which all blood cells develop) from a genetically similar, but not identical, donor.

allogenic Taken from different individuals of the same species. Also called allogeneic.

analog In chemistry, a substance that is similar, but not identical, to another.

anaplastic (an-ah-PLAS-tik) A term used to describe cancer cells that divide rapidly and have little or no resemblance to normal cells.

anemia (a-NEE-mee-a) A condition in which the number of red blood cells is below normal.

anesthesia (an-es-THEE-zha) Drugs or substances that cause loss of feeling or awareness. Local anesthetics cause loss of feeling in a part of the body. General anesthetics put the person to sleep.

anesthesiologist A doctor who specializes in giving drugs or other agents to prevent or relieve pain during surgery or other procedures being done in the hospital.

anesthetic (an-es-THET-ik) A substance that causes loss of feeling or awareness. Local anesthetics cause loss of feeling in a part of the body. General anesthetics put the person to sleep.

angiogenesis (an-gee-o-GEN-eh-sis) Blood vessel formation. Tumor angiogenesis is the growth of blood vessels from surrounding tissue to a solid tumor. This is caused by the release of chemicals by the tumor.

angiogenesis inhibitor A substance that may prevent the formation of blood vessels. In anticancer therapy, an angiogenesis inhibitor prevents the growth of blood vessels from surrounding tissue to a solid tumor.

angiostatin A protein normally made by the body. It can also be made in the laboratory, and is being studied in the treatment of cancer. Angiostatin may prevent the growth of new blood vessels from the surrounding tissue to a solid tumor. It belongs to the family of drugs called angiogenesis inhibitors.

antiangiogenesis Prevention of the growth of new blood vessels.

antibiotic (an-tih-by-AH-tik) A drug used to treat infections caused by bacteria and other microorganisms.

antibody (AN-tih-BOD-ee) A type of protein made by certain white blood cells in response to a foreign substance (antigen). Each antibody can bind to only a specific antigen. The purpose of this binding is to help destroy the antigen. Antibodies can work in several ways, depending on the nature of the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen.

antibody therapy Treatment with an antibody, a substance that can directly kill specific tumor cells or stimulate the immune system to kill tumor cells.

antiestrogen A substance that blocks the activity of estrogens, the family of hormones that promote the development and maintenance of female sex characteristics.

antifolate A substance that blocks the activity of folic acid. Antifolates are used to treat cancer. Also called folate antagonist.

antifungal A drug that treats infections caused by fungi.

antigen A substance that causes the immune system to make a specific immune response.

antigen-presenting cell APC A cell that shows antigen on its surface to other cells of the immune system. This is an important part of an immune response.

antigen-presenting cell vaccine A vaccine made of antigens and antigen-presenting cells (APCs). Also called APC vaccine.

antimetabolite A drug that is very similar to natural chemicals in a normal biochemical reaction in cells but different enough to interfere with the normal division and functions of cells.

antimicrotubule agent A drug that inhibits cell growth by stopping cell division. Antimicrotubule agents are used as treatments for cancer. Also called antimitotic agents, mitotic inhibitors, and taxanes. Docetaxel and paclitaxel are antimicrotubule agents.

antimitotic agent A drug that inhibits cell growth by stopping cell division. Antimitotic agents are used as treatments for cancer. Also called antimicrotubule agents, mitotic inhibitors, and taxanes. Docetaxel and paclitaxel are antimitotic agents.

antineoplaston A substance isolated from normal human blood and urine that is being tested as a type of treatment for some tumors and AIDS.

apheresis A procedure in which blood is collected, part of the blood such as platelets or white blood cells is taken out, and the rest of the blood is returned to the donor. Also called pheresis.

apoptosis (ap-o-TOE-sis) A normal series of events in a cell that leads to its death.

arsenic trioxide A substance that induces programmed cell death (apoptosis) in certain cancer cells. It belongs to the family of drugs called antineoplastics.

asthenia Loss or lack of bodily strength; weakness; debility.

astrocytoma (as-troe-sye-TOE-ma) A tumor that begins in the brain or spinal cord in small, star-shaped cells called astrocytes.

ataxia Loss of muscle coordination.

ataxic gait (ah-TAK-sik) Awkward, uncoordinated walking.

atypical teratoid/rhabdoid tumor ATT/RHT or AT/RT An aggressive cancer of the central nervous system, kidney, or liver that occurs in very young children.

autologous (aw-TAHL-o-gus) Taken from an individual's own tissues, cells, or DNA.

autologous bone marrow transplantation (aw-TAHL-o-gus) A procedure in which bone marrow is removed from a person, stored, and then given back to the person after intensive treatment.

autologous stem cell transplantation (aw-TAHL-o-gus) A procedure in which stem cells (cells from which all blood cells develop) are removed, stored, and then given back to the same person.

B cell A white blood cell that makes antibodies and is an important part of the immune system. B cells come from bone marrow. Also called B lymphocyte.

B lymphocyte A white blood cell that makes antibodies and is an important part of the immune system. B lymphocytes come from bone marrow. Also called B cell.

bacteremia The presence of bacteria in the blood.

benign (beh-NINE) Not cancerous. Benign tumors do not spread to tissues around them or to other parts of the body.

benign tumor (beh-NINE) A noncancerous growth that does not invade nearby tissue or spread to other parts of the body.

beta carotene A vitamin A precursor. Beta carotene belongs to the family of fat-soluble vitamins called carotenoids.

bias In a clinical trial, a flaw in the study design or method of collecting or interpreting information. Biases can lead to incorrect conclusions about what the study or trial showed.

biological response modifier (by-o-LAHJ-i-kul...) BRM. Treatment to stimulate or restore the ability of the immune system to fight infections and other diseases. Also used to lessen side effects that may be caused by some cancer treatments. Also known as biological therapy, immunotherapy, or biotherapy.

biological therapy (by-o-LAHJ-i-kul) Treatment to stimulate or restore the ability of the immune system to fight infections and other diseases. Also used to lessen side effects that may be caused by some cancer treatments. Also known as immunotherapy, biotherapy, or biological response modifier (BRM) therapy.

biopsy (BY-op-see) The removal of cells or tissues for examination under a microscope. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration.

biopsy specimen Tissue removed from the body and examined under a microscope to determine whether disease is present.

blinded study A type of study in which the patients (single-blinded) or the patients and their doctors (double-blinded) do not know which drug or treatment is being given. The opposite of a blinded study is an open label study.

blood cell count A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called complete blood count (CBC).

blood-brain barrier A network of blood vessels with closely spaced cells that makes it difficult for potentially toxic substances (such as anticancer drugs) to penetrate the blood vessel walls and enter the brain.

blood-brain barrier disruption BBBD The use of drugs to create openings between cells in the blood-brain barrier. The blood-brain barrier is a protective network of blood vessels and tissue that protects the brain from harmful substances, but can also prevent anticancer drugs from reaching the brain. Once the barrier is opened, anticancer drugs may be infused into an artery that goes to the brain, in order to treat brain tumors.

bolus A single dose of drug usually injected into a blood vessel over a short period of time. Also called bolus infusion.

bone marrow The soft, sponge-like tissue in the center of most large bones. It produces white blood cells, red blood cells, and platelets.

bone marrow ablation The destruction of bone marrow using radiation or drugs.

bone marrow aspiration (as-per-AY-shun) The removal of a small sample of bone marrow (usually from the hip) through a needle for examination under a microscope.

bone marrow biopsy (BY-op-see) The removal of a sample of tissue from the bone marrow with a needle for examination under a microscope.

bone marrow metastases Cancer that has spread from the original (primary) tumor to the bone marrow.

bone marrow transplantation (trans-plan-TAY-shun) A procedure to replace bone marrow that has been destroyed by treatment with high doses of anticancer drugs or radiation. Transplantation may be autologous (an individual's own marrow saved before treatment), allogeneic (marrow donated by someone else), or syngeneic (marrow donated by an identical twin).

bone metastases Cancer that has spread from the original (primary) tumor to the bone.

bone scan A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it collects in the bones and is detected by a scanner.

brachytherapy (BRAKE-ih-THER-a-pee) A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called internal radiation, implant radiation, or interstitial radiation therapy.

brain metastasis Cancer that has spread from the original (primary) tumor to the brain.

brain stem The part of the brain that is connected to the spinal cord.

brain stem glioma (glee-O-ma) A tumor located in the part of the brain that connects to the spinal cord (the brain stem). It may grow rapidly or slowly, depending on the grade of the tumor.

brain stem tumor A tumor in the part of the brain that connects to the spinal cord (the brain stem).

burdock Arctium lappa. A plant whose seeds and root have been used in some cultures to treat certain medical problems. It may have antioxidant effects. Also called lappa and happy major.

cancer A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the bloodstream. Lymphoma is cancer that begins in the cells of the immune system.

carcinogenesis The process by which normal cells are transformed into cancer cells.

carcinoma (KAR-si-NO-ma) Cancer that begins in the skin or in tissues that line or cover internal organs.

carcinoma in situ (KAR-si-NO-ma in SYE-too) Cancer that involves only the cells in which it began and that has not spread to nearby tissues.

cardiotoxicity Toxicity that affects the heart.

CAT scan A series of detailed pictures of areas inside the body, taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized axial tomography, computed tomography (CT scan), or computerized tomography.

cauterization (KAW-ter-ih-ZAY-shun) The destruction of tissue with a hot instrument, an electrical current, or a caustic substance.

CBC Complete blood count A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called blood cell count.

cell differentiation The process during which young, immature (unspecialized) cells take on individual characteristics and reach their mature (specialized) form and function.

cell proliferation An increase in the number of cells as a result of cell growth and cell division.

central nervous system CNS The brain and spinal cord.

central nervous system primitive neuroectodermal tumor CNS PNET A type of cancer that arises from a particular type of cell within the brain or spinal cord.

cerebellopontine (SER-uh-BEL-o-PON-teen) Having to do with two structures of the brain, the cerebellum (located at the lower back of the brain) and the pons (located at the base of the brain in front of the cerebellum) and the area between them.

cerebellum (ser-uh-BEL-um) The portion of the brain in the back of the head between the cerebrum and the brain stem. The cerebellum controls balance for walking and standing, and other complex motor functions.

cerebral hemisphere (seh-REE-bral HEM-is-feer) One half of the cerebrum, the part of the brain that controls muscle functions and also controls speech, thought, emotions, reading, writing, and learning. The right hemisphere controls the muscles on the left side of the body, and the left hemisphere controls the muscles on the right side of the body.

cerebrospinal fluid (seh-REE-broe-SPY-nal) CSF. The fluid flowing around the brain and spinal cord. Cerebrospinal fluid is produced in the ventricles in the brain.

cerebrum (seh-REE-brum) The largest part of the brain. It is divided into two hemispheres, or halves, called the cerebral hemispheres. Areas within the cerebrum control muscle functions and also control speech, thought, emotions, reading, writing, and learning.

chemoimmunotherapy Chemotherapy combined with immunotherapy. Chemotherapy uses different drugs to kill or slow the growth of cancer cells; immunotherapy uses treatments to stimulate or restore the ability of the immune system to fight cancer.

chemoradiation Treatment that combines chemotherapy with radiation therapy. Also called chemoradiotherapy.

chemotherapy (kee-mo-THER-a-pee) Treatment with anticancer drugs that are cytotoxic (toxic to cells).

choroid plexus tumor A rare type of cancer that occurs in the ventricles of the brain. It usually occurs in children younger than 2 years.

chromosome (KRO-mo-some) Part of a cell that contains genetic information. Except for sperm and eggs, all human cells contain 46 chromosomes.

chronic (KRAHN-ik) A disease or condition that persists or progresses over a long period of time.

clinical study A type of research study that uses volunteers to test new methods of screening, prevention, diagnosis, or treatment of a disease. The trial may be carried out in a clinic or other medical facility. Also called a clinical trial.

clinical trial A type of research study that uses volunteers to test new methods of screening, prevention, diagnosis, or treatment of a disease. The trial may be carried out in a clinic or other medical facility. Also called a clinical study.

CNS Central nervous system The brain and spinal cord.

CNS metastasis Cancer that has spread from the original (primary) tumor to the central nervous system.

CNS prophylaxis (pro-fih-LAK-sis) Chemotherapy or radiation therapy given to the central nervous system (CNS) as a preventive treatment. It is given to kill cancer cells that may be in the brain and spinal cord, even though no cancer has been detected there. Also called CNS sanctuary therapy.

CNS tumor A tumor of the central nervous system, including brain stem glioma, craniopharyngioma, medulloblastoma, and meningioma.

cobalt 60 A radioactive form of the metal cobalt, which is used as a source of radiation to treat cancer.

coenzyme Q10 A substance found in most tissues in the body, and in many foods. It can also be made in the laboratory. It is used by the body to produce energy for cells, and as an antioxidant. It is being studied in the treatment of cancer and in the relief of side effects caused by some cancer treatments. Also called Q10, CoQ10, vitamin Q10, and ubiquinone.

colony-stimulating factor A substance that stimulates the production of blood cells. Colony-stimulating factors include granulocyte colony-stimulating factors (also called G-CSF and filgrastim), granulocyte-macrophage colony-stimulating factors (also called GM-CSF and sargramostim), and promegapoietin.

combination chemotherapy Treatment using more than one chemotherapy drug.

complete blood count CBC A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called blood cell count.

complete remission The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured. Also called a complete response.

complete response The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured. Also called a complete remission.

computed tomography (tuh-MAH-gra-fee) CT scan. A series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized tomography and computerized axial tomography (CAT) scan.

computerized axial tomography (com-PYEW-ter-ized AX-ee-al tuh-MAH-gra-fee) A series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography (CT scan), or computerized tomography.

computerized tomography A series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized axial tomography (CAT) scan and computed tomography (CT scan).

concurrent therapy A treatment that is given at the same time as another.

consolidation therapy A type of high-dose chemotherapy often given as the second phase (after induction therapy) of a cancer treatment regimen for leukemia. Also called intensification therapy.

control group In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works.

controlled clinical trial A clinical study that includes a comparison (control) group. The comparison group receives a placebo, another treatment, or no treatment at all.

CoQ10 A substance found in most tissues in the body, and in many foods. It can also be made in the laboratory. It is used by the body to produce energy for cells, and as an antioxidant. It is being studied in the treatment of cancer and in the relief of side effects caused by some cancer treatments. Also called coenzyme Q10, Q10, vitamin Q10, and ubiquinone.

craniotomy (kray-nee-AH-toe-mee) An operation in which an opening is made in the skull.

cruciferous vegetable A member of the family of vegetables that includes kale, collard greens, broccoli, cauliflower, cabbage, Brussels sprouts, and turnips. These vegetables contain substances that may protect against cancer.

cryopreservation The process of cooling and storing cells, tissues, or organs at very low or freezing temperatures to save them for future use.

cryosurgery (KRYE-o-SER-juh-ree) Treatment performed with an instrument that freezes and destroys abnormal tissues.

cryotherapy Any method that uses cold temperature to treat disease.

CSF Cerebrospinal fluid The fluid flowing around the brain and spinal cord. CSF is produced in the ventricles of the brain.

CT scan Computed tomography scan. A series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine. Also called computerized tomography and computerized axial tomography (CAT) scan.

cumulative dose In medicine, the total amount of a drug or radiation given to a patient over time; for example, the total dose of radiation given in a series of radiation treatments.

cytology The study of cells using a microscope.

cytotoxic Cell-killing.

cytotoxic chemotherapy Anticancer drugs that kill cells, especially cancer cells.

dendritic cell A special type of antigen-presenting cell (APC) that activates T lymphocytes.

dendritic cell vaccine A vaccine made of antigens and dendritic antigen-presenting cells (APCs).

differentiation In cancer, refers to how mature (developed) the cancer cells are in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly differentiated tumor cells, which lack the structure and function of normal cells and grow uncontrollably.

disease progression Cancer that continues to grow or spread.

disease-free survival Length of time after treatment during which no cancer is found. Can be reported for an individual patient or for a study population.

disease-specific survival The percentage of subjects in a study who have survived a particular disease for a defined period of time. Usually reported as time since diagnosis or treatment. In calculating this percentage, only deaths from the disease being studied are counted. Subjects who died from some other cause are not included in the calculation.

disseminate (dih-SEM-ih-NATE) Scatter or distribute over a large area or range.

DNA Deoxyribonucleic acid The molecules inside cells that carry genetic information and pass it from one generation to the next.

dose-limiting Describes side effects of a drug or other treatment that are serious enough to prevent an increase in dose or level of that treatment.

dosimetrist do-SIM-uh-trist A person who determines the proper radiation dose for treatment.

double-blinded A clinical trial in which neither the medical staff nor the person knows which of several possible therapies the person is receiving.

dysplasia (dis-PLAY-zha) Cells that look abnormal under a microscope but are not cancer.

dyspnea Difficult or labored breathing.

EBV Epstein-Barr virus A common virus that remains dormant in most people. It has been associated with certain cancers, including Burkitt's lymphoma, immunoblastic lymphoma, and nasopharyngeal carcinoma.

edema (eh-DEE-ma) Swelling caused by excess fluid in body tissues.

efficacy Effectiveness. In medicine, the ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect.

eligibility criteria In clinical trials, requirements that must be met for an individual to be included in a study. These requirements help make sure that patients in a trial are similar to each other in terms of specific factors such as age, type and stage of cancer, general health, and previous treatment. When all participants meet the same eligibility criteria, it gives researchers greater confidence that results of the study are caused by the intervention being tested and not by other factors.

embolization (EM-bo-lih-ZAY-shun) The blocking of an artery by a clot or foreign material. Embolization can be done as treatment to block the flow of blood to a tumor.

embryonal tumor A mass of rapidly growing cells that begins in embryonic (fetal) tissue. Embryonal tumors may be benign or malignant, and include neuroblastomas and Wilms’ tumors. Also called embryoma.

emesis Vomiting.

endoscopy (en-DAHS-ko-pee) The use of a thin, lighted tube (called an endoscope) to examine the inside of the body.

endpoint In clinical trials, an event or outcome that can be measured objectively to determine whether the intervention being studied is beneficial. The endpoints of a clinical trial are usually included in the study objectives. Some examples of endpoints are survival, improvements in quality of life, relief of symptoms, and disappearance of the tumor.

ependymoma (ep-en-dih-MOE-mah) A type of brain tumor that may arise in the ventricles of the brain or in the spinal cord. Also called an ependymal tumor.

ErbB1 Epidermal growth factor receptor The protein found on the surface of some cells and to which epidermal growth factor binds, causing the cells to divide. It is found at abnormally high levels on the surface of many types of cancer cells, so these cells may divide excessively in the presence of epidermal growth factor. Also known as EGFR or HER1.

erythema Redness of the skin.

erythrocyte (eh-RITH-ro-site) A cell that carries oxygen to all parts of the body. Also called a red blood cell (RBC).

erythrocyte sedimentation rate ESR The distance red blood cells travel in one hour in a sample of blood as they settle to the bottom of a test tube. The sedimentation rate is increased in inflammation, infection, cancer, rheumatic diseases, and diseases of the blood and bone marrow. Also called sedimentation rate.

etiology The cause or origin of disease.

evaluable disease Disease that cannot be measured directly by the size of the tumor but can be evaluated by other methods specific to a particular clinical trial.

evaluable patients Patients whose response to a treatment can be measured because enough information has been collected.

Ewing's sarcoma (YOO-ingz sar-KO-ma) A type of bone cancer that usually forms in the middle (shaft) of large bones. Also called Ewing's sarcoma/primitive neuroectodermal tumor (PNET).

external radiation (ray-dee-AY-shun) Radiation therapy that uses a machine to aim high-energy rays at the cancer. Also called external-beam radiation.

external-beam radiation (ray-dee-AY-shun) Radiation therapy that uses a machine to aim high-energy rays at the cancer. Also called external radiation.

false-negative test result A test result that indicates that a person does not have a specific disease or condition when the person actually does have the disease or condition.

false-positive test result A test result that indicates that a person has a specific disease or condition when the person actually does not have the disease or condition.

filgrastim A colony-stimulating factor that stimulates the production of neutrophils (a type of white blood cell). It is a cytokine that belongs to the family of drugs called hematopoietic (blood-forming) agents. Also called granulocyte colony-stimulating factor (G-CSF).

first-line therapy The first type of therapy given for a condition or disease.

flow cytometry A method of measuring the number of cells in a sample, the percentage of live cells in a sample, and certain characteristics of cells, such as size, shape, and the presence of tumor markers on the cell surface. The cells are stained with a light-sensitive dye, placed in a fluid, and passed in a stream before a laser or other type of light. The measurements are based on how the light-sensitive dye reacts to the light.

fractionation Dividing the total dose of radiation therapy into several smaller, equal doses delivered over a period of several days.

G-CSF Granulocyte colony-stimulating factor A colony-stimulating factor that stimulates the production of neutrophils (a type of white blood cell). It is a cytokine that belongs to the family of drugs called hematopoietic (blood-forming) agents. Also called filgrastim.

gamma irradiation A type of radiation therapy that uses gamma radiation. Gamma radiation is a type of high-energy radiation that is different from x-rays.

gamma knife Radiation therapy in which high-energy rays are aimed at a tumor from many angles in a single treatment session.

gastrointestinal tract (GAS-tro-in-TES-tih-nul) The stomach and intestines.

gene The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

gene therapy Treatment that alters a gene. In studies of gene therapy for cancer, researchers are trying to improve the body's natural ability to fight the disease or to make the cancer cells more sensitive to other kinds of therapy.

gene transfer The insertion of genetic material into a cell.

genetic markers Alterations in DNA that may indicate an increased risk of developing a specific disease or disorder.

glial cell (GLEE-al) A type of cell that surrounds nerve cells and holds them in place. Glial cells also insulate nerve cells from each other.

glial tumor A general term for tumors of the central nervous system, including astrocytomas, ependymal tumors, glioblastoma multiforme, and primitive neuroectodermal tumors.

glioblastoma (glee-o-blas-TOE-ma) A general term that refers to malignant astrocytoma, a type of brain tumor.

glioblastoma multiforme (glee-o-blas-TOE-ma mul-tih-FOR-may) A type of brain tumor that forms from glial (supportive) tissue of the brain. It grows very quickly and has cells that look very different from normal cells. Also called grade IV astrocytoma.

glioma (glee-O-ma) A cancer of the brain that begins in glial cells (cells that surround and support nerve cells).

gliosarcoma A type of glioma (cancer of the brain that comes from glial, or supportive, cells).

grade The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.

grade IV astrocytoma A type of brain tumor that forms from glial (supportive) tissue of the brain. It grows very quickly and has cells that look very different from normal cells. Also called glioblastoma multiforme.

grading A system for classifying cancer cells in terms of how abnormal they appear when examined under a microscope. The objective of a grading system is to provide information about the probable growth rate of the tumor and its tendency to spread. The systems used to grade tumors vary with each type of cancer. Grading plays a role in treatment decisions.

granulocyte (GRAN-yoo-lo-site) A type of white blood cell that fights bacterial infection. Neutrophils, eosinophils, and basophils are granulocytes.

granulocyte colony-stimulating factor G-CSF A colony-stimulating factor that stimulates the production of neutrophils (a type of white blood cell). It is a cytokine that belongs to the family of drugs called hematopoietic (blood-forming) agents. Also called filgrastim.

hand-foot syndrome A condition marked by pain, swelling, numbness, tingling, or redness of the hands or feet. It sometimes occurs as a side effect of certain anticancer drugs. Also known as palmar-plantar erythodysthesia.

Hedyotis diffusa An herb used in traditional Chinese medicine to treat certain medical problems. It has been used to boost the immune system and may have anticancer effects.

Hematologic Referring to blood and blood forming tissues.

hematologist (hee-ma-TOL-o-jist) A doctor who specializes in treating blood disorders.

hemiperesis Muscular weakness affecting one side of the body.

hemoglobin (HE-muh-GLOW-bun) The substance inside red blood cells that binds to oxygen and carries it from the lungs to the tissues.

hemorrhage In medicine, loss of blood from damaged blood vessels. A hemorrhage may be internal or external, and usually involves a lot of bleeding in a short time.

hepatic Refers to the liver.

hepatoblastoma (HEP-a-toe-blas-TOE-ma) A type of liver tumor that occurs in infants and children.

hepatocellular carcinoma (HEP-a-toe-SEL-yoo-ler kar-sin-O-ma) A type of adenocarcinoma, the most common type of liver tumor.

high grade When referring to cancerous and precancerous growths, a term used to describe cells that look abnormal under a microscope. These cells are more likely to grow and spread quickly than cells in low-grade cancerous and precancerous growths.

high-dose chemotherapy An intensive drug treatment to kill cancer cells, but that also destroys the bone marrow and can cause other severe side effects including death from sepsis (infection). High-dose chemotherapy is usually followed by bone marrow or stem cell transplantation to rebuild the bone marrow.

high-energy photon therapy A type of radiation therapy that uses high-energy photons (units of light energy). High-energy photons penetrate deeply into tissues to reach tumors while giving less radiation to superficial tissues such as the skin.

histology The study of tissues and cells under a microscope.

holy thistle Cnicus benedictus A plant whose leaves, stems, and flowers have been used in some cultures to treat certain medical problems. Holy thistle may have anti-inflammatory and anticancer effects. Also called blessed thistle, St. Benedict's thistle, cardin, and spotted thistle.

hydrazine sulfate A substance that has been studied as a treatment for cancer and as a treatment for cachexia (body wasting) associated with advanced cancer.

hydrocephalus (hye-dro-SEF-uh-lus) The abnormal buildup of cerebrospinal fluid in the ventricles of the brain.

hyperbaric oxygen Oxygen that is at an atmospheric pressure higher than the pressure at sea level. Breathing hyperbaric oxygen to enhance the effectiveness of radiation therapy is being studied.

hypercalcemia (hye-per-kal-SEE-mee-a) Abnormally high blood calcium.

hyperfractionation A way of giving radiation therapy in smaller-than-usual doses two or three times a day instead of once a day.

hyperglycemia Abnormally high blood sugar.

hypernephroma (HYE-per-neh-FRO-ma) The most common type of kidney cancer. It begins in the lining of the renal tubules in the kidney. The renal tubules filter the blood and produce urine. Also called renal cell cancer.

hyperplasia (hye-per-PLAY-zha) An abnormal increase in the number of cells in an organ or tissue.

hyperthermia therapy (hye-per-THER-mee-a) A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs.

hyponatremia Deficiency of sodium in the blood.

idiopathic Describes a disease of unknown cause.

immunocompromised Having a weakened immune system caused by certain diseases or treatments.

immunodeficiency The decreased ability of the body to fight infection and disease.

immunotherapy (IM-yoo-no-THER-a-pee) Treatment to stimulate or restore the ability of the immune system to fight infections and other diseases. Also used to lessen side effects that may be caused by some cancer treatments. Also known as biological therapy, biotherapy, or biological response modifier (BRM) therapy.

implant radiation (ray-dee-AY-shun) A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, internal radiation, or interstitial radiation.

in situ cancer Early cancer that has not spread to neighboring tissue.

incidence The number of new cases of a disease diagnosed each year.

incisional biopsy (in-SIH-zhun-al BY-op-see) A surgical procedure in which a portion of a lump or suspicious area is removed for diagnosis. The tissue is then examined under a microscope.

Indian cress Nasturtium officinale Parts of the flowering plant have been used in some cultures to treat certain medical problems. It may have anticancer effects. Also called watercress.

Indian elm Ulmus fulva or Ulmus rubra The inner bark of this plant has been used in some cultures to treat certain medical problems. It may have antioxidant effects. Also called slippery elm, gray elm, red elm, and sweet elm.

Indian rhubarb Rheum palmatum or Rheum officinale The root of this plant has been used in some cultures to treat certain medical problems. It may have anti-inflammatory and anticancer effects. Also called rhubarb, da-huang, Chinese rhubarb, and Turkish rhubarb.

Indian valerian Valeriana officinalis A plant whose roots are used as a sedative and to treat certain medical conditions. It is being studied as a way to improve sleep in cancer patients undergoing treatment. Also called valerian, garden valerian, Pacific valerian, Mexican valerian, garden heliotrope, and Valerianae radix.

indolent (IN-doe-lint) A type of cancer that grows slowly.

induction therapy Treatment designed to be used as a first step toward shrinking the cancer and in evaluating response to drugs and other agents. Induction therapy is followed by additional therapy to attempt to eliminate whatever cancer remains.

infiltrating cancer Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called invasive cancer.

inflammation (in-fla-MAY-shun) Redness, swelling, pain, and/or a feeling of heat in an area of the body. This is a protective reaction to injury, disease, or irritation of the tissues.

informed consent A process in which a person learns key facts about a clinical trial, including potential risks and benefits, before deciding whether or not to participate in a study. Informed consent continues throughout the trial.

infusion A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

inoperable Describes a condition that cannot be treated by surgery.

Institutional Review Board IRB A group of scientists, doctors, clergy, and consumers at each health care facility that participates in a clinical trial. IRBs are designed to protect study participants. They review and must approve the action plan for every clinical trial. They check to see that the trial is well designed, does not involve undue risks, and includes safeguards for patients.

intensity-modulated radiation therapy IMRT A type of 3-dimensional radiation therapy that uses computer-generated images to show the size and shape of the tumor. Thin beams of radiation of different intensities are aimed at the tumor from many angles. This type of radiation therapy reduces the damage to healthy tissue near the tumor.

interferon (in-ter-FEER-on) A biological response modifier (a substance that can improve the body's natural response to infections and other diseases). Interferons interfere with the division of cancer cells and can slow tumor growth. There are several types of interferons, including interferon-alpha, -beta, and -gamma. The body normally produces these substances. They are also made in the laboratory to treat cancer and other diseases.

interleukin (in-ter-LOO-kin) A biological response modifier (substance that can improve the body's natural response to infection and disease) that helps the immune system fight infection and cancer. These substances are normally produced by the body. They are also made in the laboratory for use in treating cancer and other diseases.

interstitial radiation therapy A procedure in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, internal radiation, or implant radiation.

intraoperative radiation therapy IORT Radiation treatment aimed directly at a tumor during surgery.

intraperitoneal chemotherapy (IN-tra-per-ih-toe-NEE-al KEE-mo-THER-a-pee) Treatment in which anticancer drugs are put directly into the abdominal cavity through a thin tube.

intrathecal (in-tra-THEE-kal) Describes the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord. Drugs can be injected into the fluid or a sample of the fluid can be removed for testing.

intrathecal chemotherapy (in-tra-THEE-kal KEE-mo-THER-a-pee) Anticancer drugs that are injected into the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord.

intravenous (in-tra-VEE-nus) IV Within a blood vessel.

investigational In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the US Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered investigational in other diseases or conditions. Also called experimental.

IORT Intraoperative radiation therapy Radiation treatment aimed directly at a tumor during surgery.

IRB Institutional Review Board A group of scientists, doctors, clergy, and consumers at each health care facility that participates in a clinical trial. IRBs are designed to protect study participants. They review and must approve the action plan for every clinical trial. They check to see that the trial is well designed, does not involve undue risks, and includes safeguards for patients.

irradiation (ih-RAY-dee-AY-shun) The use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from materials called radioisotopes. Radioisotopes produce radiation and can be placed in or near the tumor or in the area near cancer cells. This type of radiation treatment is called internal radiation therapy, implant radiation, interstitial radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. Irradiation is also called radiation therapy, radiotherapy, and x-ray therapy.

irreversible toxicity Side effects that are caused by toxic substances or something harmful to the body and do not go away.

IV Intravenous (in-tra-VEE-nus). Injected into a blood vessel.

Karnofsky Performance Status KPS A standard way of measuring the ability of cancer patients to perform ordinary tasks. The Karnofsky Performance scores range from 0 to 100. A higher score means the patient is better able to carry out daily activities. KPS may be used to determine a patient's prognosis, to measure changes in a patient’s ability to function, or to decide if a patient could be included in a clinical trial.

laparoscopy (lap-a-RAHS-ko-pee) The insertion of a thin, lighted tube (called a laparoscope) through the abdominal wall to inspect the inside of the abdomen and remove tissue samples.

laparotomy (lap-a-RAH-toe-mee) A surgical incision made in the wall of the abdomen.

lentinan A beta-glucan (a type of polysaccharide) from the mushroom Lentinus edodes (shiitake mushroom). It has been studied in Japan as a treatment for cancer.

leptomeningeal Having to do with the two innermost layers of tissues that cover the brain and spinal cord.

leptomeningeal cancer A tumor that involves the tissues that cover the brain and spinal cord.

leptomeningeal metastases Cancer that has spread from the original (primary) tumor to the tissues that cover the brain and spinal cord.

lesion (LEE-zhun) An area of abnormal tissue. A lesion may be benign (noncancercous) or malignant (cancerous).

leukemia (loo-KEE-mee-a) Cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of blood cells to be produced and enter the bloodstream.

leukocyte (LOO-ko-site) A white blood cell. Refers to a blood cell that does not contain hemoglobin. White blood cells include lymphocytes, neutrophils, eosinophils, macrophages, and mast cells. These cells are made by bone marrow and help the body fight infection and other diseases.

leukopenia (LOO-ko-PEE-nya) A condition in which the number of leukocytes (white blood cells) in the blood is reduced.

lignan A member of a group of substances found in plants that have shown estrogenic and anticancer effects. Lignans have been used in some cultures to treat certain medical problems.

linac A machine that creates high-energy radiation to treat cancer, using electricity to form a stream of fast-moving subatomic particles. Also called mega-voltage (MeV) linear accelerator or a linear accelerator.

linear accelerator A machine that creates high-energy radiation to treat cancer, using electricity to form a stream of fast-moving subatomic particles. Also called mega-voltage (MeV) linear accelerator or a linac.

linseed The seed of the flax plant. It is a rich source of omega-3 fatty acid, fiber, and a compound called lignin. It is being studied in the prevention of prostate cancer. Also called flaxseed.

liver metastases Cancer that has spread from the original (primary) tumor to the liver.

local therapy Treatment that affects cells in the tumor and the area close to it.

localized Restricted to the site of origin, without evidence of spread.

locally advanced cancer Cancer that has spread only to nearby tissues or lymph nodes.

low grade When referring to cancerous and precancerous growths, a term used to describe cells that look nearly normal under a microscope. These cells are less likely to grow and spread quickly than cells in high-grade cancerous or precancerous growths.

lumbar puncture A procedure in which a needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give anticancer drugs intrathecally. Also called a spinal tap.

lymph (limf) The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.

lymph gland A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph glands filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called a lymph node.

lymph node (limf node) A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called a lymph gland.

lymphocyte (LIM-fo-site) A type of white blood cell. Lymphocytes have a number of roles in the immune system, including the production of antibodies and other substances that fight infection and diseases.

lymphoma (lim-FO-ma) Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin's lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin's lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin's lymphomas can be further divided into cancers that have an indolent (slowly progressing) course and those that have an aggressive (rapidly progressing) course. These subtypes behave and respond to treatment differently. Both Hodgkin's and non-Hodgkin's lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

lytic Having to do with lysis. In biology, lysis refers to the disintegration of a cell by disruption of its plasma membrane. Lysis can be caused by chemical or physical means (e.g., high-energy sound waves) or by a virus infection.

magnetic resonance imaging (mag-NET-ik REZ-o-nans IM-a-jing) MRI. A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as CT or x-ray. MRI is especially useful for imaging the brain, spine, the soft tissue of joints, and the inside of bones. Also called nuclear magnetic resonance imaging.

maintenance therapy Treatment that is given to help a primary (original) treatment keep working. Maintenance therapy is often given to help keep cancer in remission.

malignant (ma-LIG-nant) Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

margin The edge or border of the tissue removed in cancer surgery. The margin is described as negative or clean when the pathologist finds no cancer cells at the edge of the tissue, suggesting that all of the cancer has been removed. The margin is described as positive or involved when the pathologist finds cancer cells at the edge of the tissue, suggesting that all of the cancer has not been removed.

measurable disease A tumor that can be accurately measured in size. This information can be used to judge response to treatment.

median A statistics term. The middle value in a set of measurements.

median survival time The time from either diagnosis or treatment at which half of the patients with a given disease are found to be, or expected to be, still alive. In a clinical trial, median survival time is one way to measure how effective a treatment is.

medulloblastoma (MED-yoo-lo-blas-TOE-ma) A malignant brain tumor that begins in the lower part of the brain and that can spread to the spine or to other parts of the body. Medulloblastomas are a type of primitive neuroectodermal tumor (PNET).

mega-voltage linear accelerator MeV linear accelerator A machine that creates high-energy radiation to treat cancer, using electricity to form a stream of fast-moving subatomic particles. Also called linear accelerator or a linac.

meningeal Refers to the meninges, the tissue covering the brain and spinal cord.

meningeal metastases Cancer that has spread from the original (primary) tumor to the tissue covering the brain, spinal cord, or both.

meninges (meh-NIN-jeez) The three membranes that cover and protect the brain and spinal cord.

meningioma (meh-nin-jee-O-ma) A type of tumor that occurs in the meninges, the membranes that cover and protect the brain and spinal cord. Meningiomas usually grow slowly.

metastasis (meh-TAS-ta-sis) The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-ta-seez).

metastasize (meh-TAS-ta-size) To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic tumor are like those in the original (primary) tumor.

metastatic (MET-uh-STAT-ik) Having to do with metastasis, which is the spread of cancer from one part of the body to another.

metastatic cancer Cancer that has spread from the place in which it started to other parts of the body.

micrometastases Small numbers of cancer cells that have spread from the primary tumor to other parts of the body and are too few to be picked up in a screening or diagnostic test.

microwave thermotherapy A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs. Also called microwave therapy.

mistletoe A semiparasitic plant that grows on some types of trees. Mistletoe extracts are being studied as treatments for cancer.

mixed glioma A brain tumor that occurs in more than one type of brain cell, including astrocytes, ependymal cells, and oligodendrocytes.

modality A method of treatment. For example, surgery and chemotherapy are treatment modalities.

monoclonal antibody mAb (MAH-no-KLO-nul AN-tih-BAH-dee) A laboratory-produced substance that can potentially locate and bind to cancer cells wherever they are in the body. Many monoclonal antibodies are used in cancer detection or therapy; each one recognizes a different protein on certain cancer cells. Monoclonal antibodies can be used alone, or they can be used to deliver drugs, toxins, or radioactive material directly to a tumor.

morbidity A disease or the incidence of disease within a population. Morbidity also refers to adverse effects caused by a treatment.

Morinda citrifolia A tropical shrub. An extract from the fruit is being studied as a treatment for cancer, and extracts from the fruit, leaves, or roots have been used in some cultures to treat other diseases. Also called noni.

MRI Magnetic resonance imaging (mag-NET-ik REZ-o-nans IM-a-jing). A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as CT or x-ray. MRI is especially useful for imaging the brain, spine, the soft tissue of joints, and the inside of bones. Also called nuclear magnetic resonance imaging.

mucositis A complication of some cancer therapies in which the lining of the digestive system becomes inflamed. Often seen as sores in the mouth.

multicenter study A clinical trial that is carried out at more than one medical institution.

mutate To change the genetic material of a cell. The changes (mutations) can be harmful, beneficial, or have no effect.

mutation Any change in the DNA of a cell. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment. Mutations can be harmful, beneficial, or have no effect. If they occur in cells that make eggs or sperm, they can be inherited; if mutations occur in other types of cells, they are not inherited. Certain mutations may lead to cancer or other diseases.

myalgia (my-AL-juh) Pain in a muscle or group of muscles.

myelin (MYE-eh-lin) The fatty substance that covers and protects nerves.

myelogram (MY-eh-lo-gram) An x-ray of the spinal cord after an injection of dye into the space between the lining of the spinal cord and brain.

myeloid (MY-eh-loyd) Having to do with or resembling the bone marrow. May also refer to certain types of hematopoietic (blood-forming) cells found in the bone marrow. Sometimes used as a synonym for myelogenous; for example, acute myeloid leukemia and acute myelogenous leukemia are the same disease.

myelosuppression A condition in which bone marrow activity is decreased, resulting in fewer red blood cells, white blood cells, and platelets. Myelosuppression is a side effect of some cancer treatments. When myelosuppression is severe, it is called myeloablation.

natural killer cell NK cell A type of white blood cell that contains granules with enzymes that can kill tumor cells or microbial cells. Also called a large granular lymphocyte.

necrosis (ne-KRO-sis) Refers to the death of living tissues.

needle biopsy The removal of tissue or fluid with a needle for examination under a microscope. Also called fine-needle aspiration.

neoadjuvant therapy (NEE-o-AD-joo-vant) Treatment given before the primary treatment. Examples of neoadjuvant therapy include chemotherapy, radiation therapy, and hormone therapy.

neoplasia (NEE-o-PLAY-zha) Abnormal and uncontrolled cell growth.

neoplasm An abnormal mass of tissue that results from excessive cell division. Neoplasms may be benign (not cancerous), or malignant (cancerous). Also called tumor.

neoplastic meningitis A condition in which cancer cells spread into the meninges (membranes that surround the brain and spinal cord).

neuroblastoma Cancer that arises in immature nerve cells and affects mostly infants and children.

neurocognitive Having to do with the ability to think and reason. This includes the ability to concentrate, remember things, process information, learn, speak, and understand.

neuroectodermal tumor A tumor of the central or peripheral nervous system.

neuropathy A problem in peripheral nerve function (any part of the nervous system except the brain and spinal cord) that causes pain, numbness, tingling, swelling, and muscle weakness in various parts of the body. Neuropathies may be caused by physical injury, infection, toxic substances, disease (e.g., cancer, diabetes, kidney failure, or malnutrition), or drugs such as anticancer drugs. Also called peripheral neuropathy.

neurotoxicity The tendency of some treatments to cause damage to the nervous system.

neutropenia An abnormal decrease in the number of neutrophils, a type of white blood cell.

neutrophil (NOO-tro-fil) A type of white blood cell.

node-negative Cancer that has not spread to the lymph nodes.

node-positive Cancer that has spread to the lymph nodes.

non-Hodgkin's lymphoma A group of cancers of the lymphoid system, including B-cell lymphoma, Burkitt's lymphoma, diffuse cell lymphoma, follicular lymphoma, immunoblastic large cell lymphoma, lymphoblastic lymphoma, mantle cell lymphoma, mycosis fungoides, post-transplantation lymphoproliferative disorder, small non-cleaved cell lymphoma, and T-cell lymphoma.

noni Morinda citrifolia A tropical shrub. An extract from the fruit is being studied as a treatment for cancer, and extracts from the fruit, leaves, or roots have been used in some cultures to treat other diseases.

nonrandomized clinical trial A clinical trial in which the participants are not assigned by chance to different treatment groups. Participants may choose which group they want to be in, or they may be assigned to the groups by the researchers.

objective improvement An improvement that can be measured by the health care provider (for example, a decrease in pain can be measured by how much pain medicine the patient is taking).

objective response A measurable response.

off-label Describes the use of a prescription drug to treat a disease or condition for which the drug has not been approved by the US Food and Drug Administration.

oligoastrocytoma A rare type of brain tumor made up of two kinds of cells, oligodendrocytes and astrocytes, which are brain cells that nourish and support nerve cells. Also called mixed glioma.

oligodendroglial tumor A rare, slow-growing tumor that begins in the oligodendrocytes (brain cells that nourish and support nerve cells). Also called an oligodendroglioma.

oligodendroglioma (OL-ih-go-den-dro-glee-O-ma) A rare, slow-growing tumor that begins in the oligodendrocytes (brain cells that nourish and support nerve cells). Also called an oligodendroglial tumor.

omega-3 fatty acid A type of fat obtained in the diet and involved in immunity.

Ommaya reservoir (o-MY-a REZ-er-vwahr) A device surgically placed under the scalp and used to deliver anticancer drugs to the fluid surrounding the brain and spinal cord.

oncologist (on-KOL-o-jist) A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.

oncology The study of cancer.

oncolysis The breakdown, or lysis, of a tumor. This can occur by mechanical means, chemicals, or infectious agents such as viruses. Oncolytic viruses do not lyse most normal cells.

open label study A type of study in which both the health providers and the patients are aware of the drug or treatment being given.

operable Describes a condition that can be treated by surgery.

opportunistic infection An infection caused by an organism that does not normally cause disease. Opportunistic infections occur in people with weakened immune systems.

osteosarcoma (AHS-tee-o-sar-KO-ma) A cancer of the bone that usually affects the large bones of the arm or leg. It occurs most commonly in young people and affects more males than females. Also called osteogenic sarcoma.

ototoxicity Being poisonous to or exerting a deleterious effect upon the eighth nerve or upon the organs of hearing and balance.

outpatient A patient who visits a health care facility for diagnosis or treatment without spending the night. Sometimes called a day patient.

overall survival The percentage of subjects in a study who have survived for a defined period of time. Usually reported as time since diagnosis or treatment. Also called the survival rate.

p53 gene A tumor suppressor gene that normally inhibits the growth of tumors. This gene is altered in many types of cancer.

palliative care (PAL-ee-yuh-tiv) Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal of palliative care is to prevent or treat as early as possible the symptoms of the disease, side effects caused by treatment of the disease, and psychological, social, and spiritual problems related to the disease or its treatment. Also called comfort care, supportive care, and symptom management.

palliative therapy (PAL-ee-yuh-tiv) Treatment given to relieve the symptoms and reduce the suffering caused by cancer and other life-threatening diseases. Palliative cancer therapies are given together with other cancer treatments, from the time of diagnosis, through treatment, survivorship, recurrent or advanced disease, and at the end of life.

paresis Slight or incomplete paralysis.

paresthesias Abnormal touch sensations, such as burning or prickling, that occur without an outside stimulus.

partial remission A decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment. Also called partial response.

partial response A decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment.

pathologist (pa-THOL-o-jist) A doctor who identifies diseases by studying cells and tissues under a microscope.

pathology report The description of cells and tissues made by a pathologist based on microscopic evidence, and sometimes used to make a diagnosis of a disease.

pediatric (pee-dee-AT-rik) Having to do with children.

performance status A measure of how well a patient is able to perform ordinary tasks and carry out daily activities.

perioperative Around the time of surgery; usually lasts from the time of going into the hospital or doctor's office for surgery until the time the patient goes home.

peripheral blood Blood circulating throughout the body.

peripheral neuropathy A condition of the nervous system that causes numbness, tingling, burning or weakness. It usually begins in the hands or feet, and can be caused by certain anticancer drugs.

PET scan Positron emission tomography scan. A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body.

phase I trial The first step in testing a new treatment in humans. These studies test the best way to give a new treatment (for example, by mouth, intravenous infusion, or injection) and the best dose. The dose is usually increased a little at a time in order to find the highest dose that does not cause harmful side effects. Because little is known about the possible risks and benefits of the treatments being tested, phase I trials usually include only a small number of patients who have not been helped by other treatments.

phase I/II trial A trial to study the safety, dosage levels, and response to a new treatment.

phase II trial A study to test whether a new treatment has an anticancer effect (for example, whether it shrinks a tumor or improves blood test results) and whether it works against a certain type of cancer.

phase II/III trial A trial to study response to a new treatment and the effectiveness of the treatment compared with the standard treatment regimen.

phase III trial A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment seems to work in phases I and II. Phase III trials may include hundreds of people.

phase IV trial After a treatment has been approved and is being marketed, it is studied in a phase IV trial to evaluate side effects that were not apparent in the phase III trial. Thousands of people are involved in a phase IV trial.

phenylacetate A drug being studied in the treatment of cancer.

phenylbutyrate An anticancer drug that belongs to the family of drugs called differentiating agents.

pheresis (fer-E-sis) A procedure in which blood is collected, part of the blood such as platelets or white blood cells is taken out, and the rest of the blood is returned to the donor. Also called apheresis.

Philadelphia chromosome An abnormality of chromosome 22 in which part of chromosome 9 is transferred to it. Bone marrow cells that contain the Philadelphia chromosome are often found in chronic myelogenous leukemia.

phlebitis Inflammation of a vein.

phlebotomy The puncture of a vein with a needle for the purpose of drawing blood. Also called venipuncture.

photodynamic therapy (foe-toe-dye-NAM-ik) Treatment with drugs that become active when exposed to light. These drugs kill cancer cells.

photopheresis A procedure in which blood is treated outside the body, with ultraviolet light and drugs that become active when exposed to light, and then returned to the body. It is being studied as a treatment for some blood and bone marrow diseases and graft-versus-host disease (GVHD). Also called extracorporeal photophoresis.

pilocytic (PI-lo-SIT-ik) Made up of cells that look like fibers when viewed under a microscope.

pilot study The initial study examining a new method or treatment.

pineoblastoma (PIN-ee-o-blas-TOE-ma) A fast growing type of brain tumor that occurs in or around the pineal gland, a tiny organ near the center of the brain.

placebo-controlled Refers to a clinical study in which the control patients receive a placebo.

plasma (PLAS-ma) The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

platelet (PLAYT-let) A type of blood cell that helps prevent bleeding by causing blood clots to form. Also called a thrombocyte.

PNET Primitive neuroectodermal tumor One of a group of cancers that develop from the same type of early cells, and share certain biochemical and genetic features. Some PNETs develop in the brain and central nervous system (CNS-PNET), and others develop in sites outside of the brain such as the limbs, pelvis, and chest wall (peripheral PNET).

polymerase chain reaction PCR A laboratory method used to make many copies of a specific DNA sequence.

pons Part of the central nervous system, located at the base of the brain, between the medulla oblongata and the midbrain. It is part of the brainstem.

port-a-cath An implanted device through which blood may be withdrawn and drugs may be infused without repeated needle sticks. Also called a port.

positron emission tomography scan PET scan A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body.

postmortem After death. Often used to describe an autopsy.

postoperative After surgery.

preclinical study Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done.

primary tumor The original tumor.

primitive neuroectodermal tumor PNET One of a group of cancers that develop from the same type of early cells, and share certain biochemical and genetic features. Some PNETs develop in the brain and central nervous system (CNS-PNET), and others develop in sites outside of the brain such as the limbs, pelvis, and chest wall (peripheral PNET).

progression Increase in the size of a tumor or spread of cancer in the body.

progression-free survival One type of measurement that can be used in a clinical study or trial to help determine whether a new treatment is effective. It refers to the probability that a patient will remain alive, without the disease getting worse.

progressive disease Cancer that is increasing in scope or severity.

protocol An action plan for a clinical trial. The plan states what the study will do, how, and why. It explains how many people will be in it, who is eligible to participate, what study agents or other interventions they will be given, what tests they will receive and how often, and what information will be gathered.

proton beam radiation therapy (…ray-dee-AY-shun…) A type of radiation therapy that uses protons generated by a special machine. A proton is a type of high-energy radiation that is different from an x-ray.

pulmonary Relating to the lungs.

quality of life The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life. These studies measure aspects of an individual's sense of well-being and ability to carry out various tasks.

radiation (ray-dee-AY-shun) Energy released in the form of particles or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, and medical x-rays.

radiation physicist A person who makes sure that the radiation machine delivers the right amount of radiation to the correct site in the body. The physicist works with the radiation oncologist to choose the treatment schedule and dose that has the best chance of killing the most cancer cells.

radiation surgery A radiation therapy technique that delivers radiation directly to the tumor while sparing the healthy tissue. Also called radiosurgery and stereotactic external beam irradiation.

radiation therapy (ray-dee-AY-shun THER-ah-pee) The use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy, implant radiation, or brachytherapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. Also called radiotherapy.

radioactive seed A small, radioactive pellet that is placed in or near a tumor. Cancer cells are killed by the energy given off as the radioactive material decays (breaks down).

radioimmunotherapy Treatment with a radioactive substance that is linked to an antibody that will attach to the tumor when injected into the body.

radiolabeled Any compound that has been joined with a radioactive substance.

radiologist (RAY-dee-OL-o-jist) A doctor who specializes in creating and interpreting pictures of areas inside the body. The pictures are produced with x-rays, sound waves, or other types of energy.

radiology The use of radiation (such as x-rays) or other imaging technologies (such as ultrasound and magnetic resonance imaging) to diagnose or treat disease.

radionecrosis Destruction of tissue or ulceration caused by radiation.

radiopharmaceutical A drug containing a radioactive substance that is used in the diagnosis and treatment of cancer and in pain management of bone metastases. Also called a radioactive drug.

radiosurgery A radiation therapy technique that delivers radiation directly to the tumor while sparing the healthy tissue. Also called radiation surgery and stereotactic external beam irradiation.

radiotherapy (RAY-dee-o-THER-a-pee) The use of high-energy radiation from x-rays, gamma rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy, implant radiation, or brachytherapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. Also called radiation therapy.

randomization When referring to an experiment or clinical trial, the process by which animal or human subjects are assigned by chance to separate groups that compare different treatments or other interventions. Randomization gives each participant an equal chance of being assigned to any of the groups.

randomized clinical trial A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.

RBC Red blood cell. RBCs carry oxygen to all parts of the body.

recur To occur again.

recurrence The return of cancer, at the same site as the original (primary) tumor or in another location, after the tumor had disappeared.

recurrent cancer Cancer that has returned after a period of time during which the cancer could not be detected. The cancer may come back to the same site as the original (primary) tumor or to another place in the body.

red blood cell RBC. A cell that carries oxygen to all parts of the body. Also called an erythrocyte.

red clover Trifolium pratense. A plant whose flowers have been used in some cultures to treat certain medical problems. It is being studied in the relief of menopausal symptoms and may have anticancer effects. Also called purple clover and wild clover.

refractory In medicine, describes a disease or condition that does not respond to treatment.

refractory cancer Cancer that has not responded to treatment.

regimen A treatment plan that specifies the dosage, the schedule, and the duration of treatment.

regression A decrease in the size of a tumor or in the extent of cancer in the body.

relapse The return of signs and symptoms of cancer after a period of improvement.

relative survival rate A specific measurement of survival. For cancer, the rate is calculated by adjusting the survival rate to remove all causes of death except cancer. The rate is determined at specific time intervals, such as 2 years and 5 years after diagnosis.

remission A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although cancer still may be in the body.

remote brachytherapy A type of internal radiation treatment in which the radioactive source is removed between treatments. Also called high-dose-rate remote brachytherapy or high-dose-rate remote radiation therapy.

resectable (ree-SEK-tuh-bull) Part or all of an organ that can be removed with surgery.

resected Surgical removal of part or all of an organ.

resection (ree-SEK-shun) Removal of tissue or part or all of an organ by surgery.

residual disease Cancer cells that remain after attempts to remove the cancer have been made.

resistance Failure of a cancer to shrink after treatment.

response The shrinking of a tumor with cancer therapy.

response rate The percentage of patients whose cancer shrinks or disappears after treatment.

retinoblastoma An eye cancer that most often occurs in children younger than 5 years. It occurs in hereditary and nonhereditary (sporadic) forms.

retinoid Vitamin A or a vitamin A-like compound.

retinol Vitamin A. It is essential for proper vision and healthy skin and mucous membranes. Retinol is being studied for cancer prevention; it belongs to the family of drugs called retinoids.

retrospective study A study that compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls). Researchers study the medical and lifestyle histories of the people in each group to learn what factors may be associated with the disease or condition. For example, one group may have been exposed to a particular substance that the other was not. Also called a case-control study.

rhabdoid tumor A malignant tumor of either the central nervous system (CNS) or the kidney. Malignant rhabdoid tumors of the CNS often have an abnormality of chromosome 22. These tumors usually occur in children younger than 2 years.

rhabdomyosarcoma A malignant tumor of muscle tissue.

scan A picture of structures inside the body. Scans often used in diagnosing, staging, and monitoring disease include liver scans, bone scans, and computed tomography (CT) or computerized axial tomography (CAT) scans and magnetic resonance imaging (MRI) scans. In liver scanning and bone scanning, radioactive substances that are injected into the bloodstream collect in these organs. A scanner that detects the radiation is used to create pictures. In CT scanning, an x-ray machine linked to a computer is used to produce detailed pictures of organs inside the body. MRI scans use a large magnet connected to a computer to create pictures of areas inside the body.

schedule In clinical trials, the step-by-step plan for how patients are to be treated; for example, which drugs are to be given, the order and method by which they are to be given, the length of time of each infusion, the amount of time between courses, and the total length of treatment.

second-line therapy Treatment that is given when initial treatment (first-line therapy) doesn’t work, or stops working.

second-look surgery Surgery performed after primary treatment to determine whether tumor cells remain.

secondary cancer A term that is used to describe either a new primary cancer or cancer that has spread from the place in which it started to other parts of the body.

sedimentation rate The distance red blood cells travel in one hour in a sample of blood as they settle to the bottom of a test tube. The sedimentation rate is increased in inflammation, infection, cancer, rheumatic diseases, and diseases of the blood and bone marrow. Also called erythrocyte sedimentation rate.

selection bias An error in choosing the individuals or groups to take part in a study. Ideally, the subjects in a study should be very similar to one another and to the larger population from which they are drawn (for example, all individuals with the same disease or condition). If there are important differences, the results of the study may not be valid.

sepsis (SEP-sis) The presence of bacteria or their toxins in the blood or tissues.

shunt A surgeon implants or creates a shunt to move blood or other fluid from one part of the body to another part. For example, a surgeon may implant a tube to drain cerebrospinal fluid from the brain to the abdomen. A surgeon may also change normal blood flow by joining two blood vessels together.

simulation In cancer treatment, a process used to plan radiation therapy so that the target area is precisely located and marked.

somnolence Sleepiness or unnatural drowsiness.

spinal tap A procedure in which a needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs. Also called a lumbar puncture.

spleen An organ that is part of the lymphatic system. The spleen produces lymphocytes, filters the blood, stores blood cells, and destroys old blood cells. It is located on the left side of the abdomen near the stomach.

stable disease Cancer that is neither decreasing nor increasing in extent or severity.

stage The extent of a cancer within the body. If the cancer has spread, the stage describes how far it has spread from the original site to other parts of the body.

staging (STAY-jing) Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body. It is important to know the stage of the disease in order to plan the best treatment.

standard of care In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with the standard of care. Also called standard therapy or best practice.

standard therapy In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with standard therapy. Also called standard of care or best practice.

stem cell transplantation A method of replacing immature blood-forming cells that were destroyed by cancer treatment. The stem cells are given to the person after treatment to help the bone marrow recover and continue producing healthy blood cells.

stent A device placed in a body structure (such as a blood vessel or the gastrointestinal tract) to provide support and keep the structure open.

stereotactic biopsy (STAIR-ee-o-TAK-tik BY-op-see) A biopsy procedure that uses a computer and a three-dimensional scanning device to find a tumor site and guide the removal of tissue for examination under a microscope.

stereotactic body radiation therapy A radiation therapy technique that uses special equipment to position the patient and precisely deliver a large radiation dose to a tumor and not to normal tissue.

stereotactic external-beam radiation A radiation therapy technique for brain tumors that uses a rigid head frame attached to the skull. The frame is used to help aim high-dose radiation beams directly at the tumors and not at normal brain tissue. This procedure does not involve surgery. Also called stereotactic radiation therapy, stereotactic radiosurgery, and stereotaxic radiosurgery.

stereotactic radiation therapy (STAIR-ee-o-TAK-tik ray-dee-AY-shun) A radiation therapy technique for brain tumors that uses a rigid head frame that is attached to the skull. The frame is used to help aim high-dose radiation beams directly at the tumors and not at normal brain tissue. This procedure does not involve surgery. Also called stereotactic external-beam radiation, stereotactic radiosurgery, and stereotaxic radiosurgery.

stereotactic radiosurgery (STAIR-ee-o-TAK-tik...) A radiation therapy technique for brain tumors that uses a rigid head frame that is attached to the skull. The frame is used to help aim high-dose radiation beams directly at the tumors and not at normal brain tissue. This procedure does not involve surgery. Also called stereotactic external-beam radiation, stereotactic radiation therapy, and stereotaxic radiosurgery.

stomatitis Inflammation or irritation of the mucous membranes in the mouth.

subjective improvement An improvement that is reported by the patient, but cannot be measured by the healthcare provider (for example, "I feel better").

survival rate The percentage of people in a study or treatment group who are alive for a given period of time after diagnosis. This is commonly expressed as 5-year survival.

syncope A temporary suspension of consciousness due to generalized cerebral ischemia; a faint or swoon.

systemic (sis-TEM-ik) Affecting the entire body.

systemic chemotherapy Treatment with anticancer drugs that travel through the bloodstream, reaching and affecting cells all over the body.

systemic disease Disease that affects the whole body.

therapy Treatment.

thrombocyte (THROM-bo-site) A blood cell that helps prevent bleeding by causing blood clots to form. Also called a platelet.

thrombocytopenia, thrombopenia A decrease in the number of platelets in the blood that may result in easy bruising and excessive bleeding from wounds or bleeding in mucous membranes and other tissues.

thrombosis (throm-BOW-sis) The formation or presence of a blood clot inside a blood vessel.

time to progression A measure of time after a disease is diagnosed (or treated) until the disease starts to get worse.

TNM staging system A system for describing the extent of cancer in a patient’s body. T describes the size of the tumor and whether it has invaded nearby tissue, N describes any lymph nodes that are involved, and M describes metastasis (spread of cancer from one body part to another).

total parenteral nutrition TPN. Intravenous (into a vein) feeding that provides necessary nutrients when a person is unable to eat normally.

total-body irradiation Radiation therapy to the entire body. Usually followed by bone marrow or peripheral stem cell transplantation.

toxic Having to do with poison or something harmful to the body. Toxic substances usually cause unwanted side effects.

transformation The change that a normal cell undergoes as it becomes malignant.

transfusion (trans-FYOO-zhun) The infusion of components of blood or whole blood into the bloodstream. The blood may be donated from another person, or it may have been taken from the person earlier and stored until needed.

treatment field In radiation therapy, the place on the body where the radiation beam is aimed.

tumor (TOO-mer) A mass of excess tissue that results from abnormal cell division. Tumors perform no useful body function. They may be benign (not cancerous) or malignant (cancerous).

tumor board review A treatment planning approach in which a number of doctors who are experts in different specialties (disciplines) review and discuss the medical condition and treatment options of a patient. In cancer treatment, a tumor board review may include that of a medical oncologist (who provides cancer treatment with drugs), a surgical oncologist (who provides cancer treatment with surgery), and a radiation oncologist (who provides cancer treatment with radiation). Also called a multidisciplinary opinion.

tumor burden Refers to the number of cancer cells, the size of a tumor, or the amount of cancer in the body. Also called tumor load.

tumor debulking Surgically removing as much of the tumor as possible.

tumor load Refers to the number of cancer cells, the size of a tumor, or the amount of cancer in the body. Also called tumor burden.

tumor marker A substance sometimes found in the blood, other body fluids, or tissues. A high level of tumor marker may mean that a certain type of cancer is in the body. Examples of tumor markers include CA 125 (ovarian cancer), CA 15-3 (breast cancer), CEA (ovarian, lung, breast, pancreas, and gastrointestinal tract cancers), and PSA (prostate cancer). Also called biomarker.

tumor necrosis factor (TOO-mer ne-KRO-sis) A type of biological response modifier (a substance that can improve the body's natural response to disease). Three types of tumor necrosis factor have been identified: alpha, beta, and gamma. Tumor necrosis factor seems to play a role in the breakdown of cancer cells.

tumor suppressor gene (TOO-mer) Genes in the body that can suppress or block the development of cancer.

tumor-specific antigen A protein or other molecule that is unique to cancer cells or is much more abundant in them. These molecules are usually found in the plasma (outer) membrane, and they are thought to be potential targets for immunotherapy or other types of anticancer treatment.

uncontrolled study A clinical study that lacks a comparison (i.e., a control) group.

undifferentiated A term used to describe cells or tissues that do not have specialized ("mature") structures or functions. Undifferentiated cancer cells often grow and spread quickly.

unresectable Unable to be removed with surgery.

vaccine therapy A type of treatment that uses a substance or group of substances to stimulate the immune system to destroy a tumor or infectious microorganisms such as bacteria or viruses.

valerian Valeriana officinalis A plant whose roots are used as a sedative and to treat certain medical conditions. It is being studied as a way to improve sleep in cancer patients undergoing treatment. Also called garden valerian, Indian valerian, Pacific valerian, Mexican valerian, garden heliotrope, and Valerianae radix.

WBC White blood cell. Refers to a blood cell that does not contain hemoglobin. White blood cells include lymphocytes, neutrophils, eosinophils, macrophages, and mast cells. These cells are made by bone marrow and help the body fight infection and other diseases.

wild clover Trifolium pratense. A plant whose flowers have been used in some cultures to treat certain medical problems. It is being studied in the relief of menopausal symptoms and may have anticancer effects. Also called red clover and purple clover.

Wobe-Mugos E A mixture made from an extract of the calf thymus gland and enzymes (proteins that speed up chemical reactions in the body) from the papaya plant, the pancreas of cows, and the pancreas of pigs. It has been used in Europe as a treatment for a variety of cancers and for herpes virus infections.

x-ray therapy The use of high-energy radiation from x-rays to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from materials called radioisotopes. Radioisotopes produce radiation and can be placed in or near the tumor or in the area near cancer cells. This type of radiation treatment is called internal radiation therapy, implant radiation, interstitial radiation, or brachytherapy. Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that circulates throughout the body. X-ray therapy is also called radiation therapy, radiotherapy, and irradiation.

xenograft The cells of one species transplanted to another species.

yttrium (IH-tree-um) A rare elemental metal. A radioactive form of yttrium is used in radiation therapy and some types of immunotherapy.

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