medulloblastoma(MED-yoo-loh-blas-TOH-muh) 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…
mega-voltage linear acceleratorA machine that uses electricity to form a stream of fast-moving subatomic particles. This creates high-energy radiation that may be used to treat cancer.
MegaceA drug used to block estrogen and suppress the effects of estrogen and androgens.
megestrolA drug used to block estrogen and suppress the effects of estrogen and androgens.
MeiosisA special form of cell division in which each daughter cell receives half the amount of DNA as the parent cell.
MEK inhibitor AZD6244(... in-HIH-bih-ter...) A substance being studied in the treatment of several types of cancer.
Melan-A proteinA substance found on the surface of melanoma cells. It is being used to develop cancer vaccines that may help the immune system kill cancer cells.
melanin(MEH-luh-nin) A pigment that gives color to skin and eyes and helps protect it from damage by ultraviolet light.
melanocortin 1 receptor(meh-LA-nuh-KOR-tin 1 reh-SEP-ter) A protein found in skin and eye cells that make melanin (a pigment that gives color to the skin and helps protect it…
Melanocyte(mel-AN-o-site) A cell in the skin and eyes that produces and contains the pigment called melanin.
melanoma(MEH-luh-NOH-muh) A form of cancer that begins in melanocytes (cells that make the pigment melanin).
melanoma in situ(MEH-luh-NOH-muh in SY-too) Abnormal melanocytes (cells that make melanin, the pigment that gives skin its color) are found in the epidermis (outer layer…
melanoma vaccineA cancer vaccine prepared from human melanoma cancer cells. It can be used alone or with other therapy in treating melanoma.
melanotropin receptor(meh-LA-nuh-TROH-pin reh-SEP-ter) A protein found in skin and eye cells that make melanin (a pigment that gives color to the skin and helps protect it…
melatonin(MEH-luh-TOH-nun) A hormone made by the pineal gland (tiny organ near the center of the brain).
melphalanA drug that is used to treat multiple myeloma and ovarian epithelial cancer and is being studied in the treatment of other types of cancer.
memantine hydrochloride(MEH-mun-teen HY-droh-KLOR-ide) A drug used to treat dementia caused by Alzheimer disease.
membraneA very thin layer of tissue that covers a surface.
MEN syndrome(... SIN-drome) An inherited condition that may result in the development of cancers of the endocrine system.
MEN-10755An anticancer drug that belongs to the family of drugs called antitumor antibiotics.
MEN1 syndrome(... SIN-drome) A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas.
meningeal(meh-NIN-jee-ul) Having to do with the meninges (three thin layers of tissue that cover and protect the brain and spinal cord).
meningeal metastasis(meh-NIN-jee-ul meh-TAS-tuh-sis) Cancer that has spread from where it first formed in the body to the meninges (three thin layers of tissue that cover and…
meninges(meh-NIN-jees) The three thin layers of tissue that cover and protect the brain and spinal cord.
meningioma(meh-NIN-jee-OH-muh) A type of slow-growing tumor that forms in the meninges (thin layers of tissue that cover and protect the brain and spinal cord).
meningitis(meh-nin-JY-tis) Inflammation of the meninges (three thin layers of tissue that cover and protect the brain and spinal cord).
Menopausal(men'o-pawz"ul) describes the time of life when the ovaries stop making estrogen.
menopausal hormone therapy(MEH-nuh-PAW-zul HOR-mone THAYR-uh-pee) Hormones (estrogen, progesterone, or both) given to women after menopause to replace the hormones no longer…
Menopause(MEH-nuh-PAWZ) The time of life when a woman's menstrual periods stop. A woman is in menopause when she hasn't had a period for 12 months in a row.
Menses(men'sees) the monthly flow of blood from the genital tract of women. Also called menstruating or the period.
menstrual cycle(MEN-stroo-al) The monthly cycle of hormonal changes from the beginning of one menstrual period to the beginning of the next.
menstrual period(MEN-stroo-al PEER-ee-od) The periodic discharge of blood and tissue from the uterus.
menstruation(MEN-stroo-AY-shun) Periodic discharge of blood and tissue from the uterus. From puberty until menopause, menstruation occurs about every 28 days when a…
mental healthA person's overall psychological and emotional condition. Good mental health is a state of well-being in which a person is able to cope with everyday…
mental health counselorA specialist who can talk with patients and their families about emotional and personal matters, and can help them make decisions.
meperidine(meh-PAYR-ih-deen) A morphine-like drug used to relieve medium to severe pain. It is a type of opioid analgesic and may be habit-forming.
mercaptopurineA drug used to treat acute lymphatic leukemia. It belongs to the family of drugs called antimetabolites. Also called Purinethol.
mercuryA silver-white, poisonous metal that is a liquid at ordinary temperatures. It is commonly used in thermometers and amalgams, and has been used as an…
mercy killingAn easy or painless death, or the intentional ending of the life of a person suffering from an incurable or painful disease at his or her request.
meridian(meh-RID-ee-un) In traditional Chinese medicine, one of 20 channels that form a network through which qi (the body's vital energy) flows and that connect…
Merkel cell cancer(MER-kel sel KAN-ser) A rare type of cancer that forms on or just beneath the skin, usually in parts of the body that have been exposed to the sun.
mesenchymalRefers to cells that develop into connective tissue, blood vessels, and lymphatic tissue.
mesenteric membraneThe peritoneal membrane that attaches the intestines to the abdominal wall near the back.
mesnaA drug that helps protect the kidneys and bladder from the toxic effects of anticancer drugs such as ifosfamide and cyclophosphamide.
mesonephromaA rare type of tumor, usually of the female genital tract, in which the insides of the cells look clear when viewed under a microscope.
mesothelin(mez-oh-THEE-lin) A protein found on the surface of certain types of normal cells and cancer cells.
mesothelioma(meh-zuh-thee-lee-OH-muh) A benign (noncancerous) or malignant (cancerous) tumor affecting the lining of the chest or abdomen.
metabolic(MEH-tuh-BAH-lik) Having to do with metabolism (the total of all chemical changes that take place in a cell or an organism to produce energy and basic…
metabolic acidosis(MEH-tuh-BAH-lik A-sih-DOH-sis) A condition in which the blood is too acidic. It may be caused by severe illness or sepsis (bacteria in the bloodstream).
Metabolic Disorder(MEH-tuh-BAH-lik dis-OR-der) A condition in which normal metabolic processes are disrupted, usually because of a missing enzyme.
metabolic therapy(MEH-tuh-BAH-lik THAYR-uh-pee) Treatment to correct changes in metabolism that can be caused by disease.
metabolic type(MEH-tuh-BAH-lik tipe) In alternative medicine, a theory that people fall into one of three groups (protein, carbohydrate, or mixed type) based on the…
metabolism(meh-TA-boh-lih-zum) The total of all chemical changes that take place in a cell or an organism.
metabolite(meh-TA-boh-lite) A substance made or used when the body breaks down food, drugs or chemicals, or its own tissue (for example, fat or muscle tissue).
metallic(meh-TA-lik) Having to do with metal. Some cancer treatments may change the sense of taste and cause foods to have a metallic taste.
MetaplasiaA change of cells to a form that does not normally occur in the tissue in which it is found.
metaplastic carcinomaA general term used to describe cancer that begins in cells that have changed into another cell type (for example, a squamous cell of the esophagus…
metastasectomy(meh-TAS-tuh-SEK-toh-mee) Surgery to remove one or more metastases (tumors formed from cells that have spread from the primary tumor).
metastasesWhen cancer spreads to another location in the body. For example, if breast cancer cells spread to the bone, this is called a "breast cancer metastasis."
metastasis(meh-TAS-tuh-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…
metastasize(meh-TAS-tuh-size) To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic…
Metastatic(meh-tuh-STA-tik) Having to do with metastasis, which is the spread of cancer from one part of the body to another.
metastatic cancer(meh-tuh-STA-tik KAN-ser) Cancer that has spread from the place in which it started to other parts of the body.
meteorismSwelling of the abdomen caused by gas in the intestines or peritoneal cavity. Also called tympanites.
Methadone(MEH-thuh-DONE) A morphine-like drug used to treat severe pain and to prevent withdrawal symptoms in patients who are addicted to heroin or other opiates.
methodology(MEH-thuh-DAH-loh-jee) In medicine, the rules and procedures for doing research and evaluating results.
methotrexate(meh-thuh-TREK-sayt) A drug used to treat some types of cancer, severe skin conditions such as psoriasis, and rheumatoid arthritis.
methoxsalen(meh-THOX-uh-len) A drug used together with UV light to treat psoriasis, vitiligo, and skin nodules of cutaneous T-cell lymphoma.
methoxypolyethylene glycol epoetin beta(meh-THOK-see-PAH-lee-EH-thih-leen GLY-kol ee-POH-eh-tin...) A substance being studied in the treatment of anemia in patients who are receiving…
methyl-5-aminolevulinateA drug used in photodynamic therapy; it is absorbed by tumor cells and, when exposed to light, becomes active and kills the cancer cells.
methylnaltrexone(MEH-thul-nal-TREK-sone) The active ingredient in a drug used to relieve certain side effects caused by treatment with opiods (pain killers similar to…
methylnaltrexone bromide(MEH-thul-nal-TREK-sone BROH-mide) A drug used to relieve certain side effects caused by treatment with opiods (pain killers similar to morphine), such as…
methylphenidateA drug that is a central nervous system stimulant.
metoclopramide(met-oh-KLOH-pruh-mide) A drug that increases the motility (movements and contractions) of the stomach and upper intestine.
metronidazoleA drug that is used to treat infection and is being studied in the treatment of cancer. It is a type of antibacterial, antiprotozoal, and anthelmintic.
metronomic therapy(MEH-truh-NAH-mik THAYR-uh-pee) Continuous or frequent treatment with low doses of anticancer drugs, often given with other methods of therapy.
MeV linear accelerator(...LIH-nee-er ak-SEH-luh-RAY-tur) A machine that uses electricity to form a stream of fast-moving subatomic particles.
Mevacor(MEV-uh-kor) A drug used to lower the amount of cholesterol in the blood. It is also being studied in the prevention and treatment of some types of cancer.
Mexican valerianA plant whose roots are used as a sedative and to treat certain medical conditions.
MG98An anticancer drug that belongs to the family of drugs called antisense compounds. These drugs interfere with production of certain proteins in the cell.
MGUSA benign condition in which there is a higher-than-normal level of a protein called M protein in the blood.
microcalcification(MY-krow-kal-si-fi-KAY-shun) A tiny deposit of calcium in the breast that cannot be felt but can be detected on a mammogram.
Microcalcifications or calcifications(mi'-crow-cal-sih-fih-cay"-shuns) are a finding reported on mammograms. They are an indicator of increased in breast activity in some cells.
microfluidic device(MY-kroh-floo-IH-dik dee-VICE) An instrument that uses very small amounts of fluid on a microchip to do certain laboratory tests.
micrometastasis(MY-kroh-meh-TAS-tuh-sis) 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…
micromolar(MY-kroh-MOH-lur) A concentration of 1/1,000,000 (one millionth) molecular weight per liter (mol/L).
micronutrient(MY-kroh-NOO-tree-ent) A substance the body needs in tiny amounts to grow and stay healthy. Examples are vitamins and minerals.
microorganismAn organism that can be seen only through a microscope. Microorganisms include bacteria, protozoa, algae, and fungi.
microsatelliteA short sequence of DNA, usually 1 to 4 basepairs (a unit of DNA), that is repeated together in a row along the DNA molecule.
microsatellite instability(MY-kroh-SA-teh-lite in-stuh-BIH-lih-tee) A change that occurs in the DNA of certain cells (such as tumor cells) in which the number of repeats of…
microscopicToo small to be seen without a microscope.
microsphere(MY-kroh-sfeer) A very tiny, hollow, round particle made from glass, ceramic, plastic, or other materials.
microstagingA technique used to help determine the stage (extent) of melanoma and certain squamous cell cancers.
microwave acupuncture(MY-kroh-WAYV AK-yoo-PUNK-cher) A type of acupuncture in which a microwave device is attached to an acupuncture needle to give microwave radiation at an…
microwave therapy(MY-kroh-WAYV THAYR-uh-pee) A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make cancer…
microwave thermotherapy(MY-kroh-WAYV THER-moh-THAYR-uh-pee) A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make…