Cancer Education at Banner MD Anderson Cancer Center  

Glossary of Cancer Terms - M

 

M protein An antibody or part of an antibody found in unusually large amounts in the blood or urine of people with multiple myeloma and other types of plasma cell tumors. Also called monoclonal protein.

M200 A monoclonal antibody that is being studied in the treatment of some types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to cancer cells. M200 binds to a protein that is found on cells that line some tumor blood vessels. It belongs to the family of drugs called angiogenesis inhibitors. Also called volociximab.

ma huang Ephedra sinica. A shrub native to China and India. The stems and roots are used in traditional medicine as a diuretic and for asthma, bronchitis, and cough. It has also been promoted as a decongestant, a weight loss aid and as a supplement to increase energy. Ma huang may cause high blood pressure, increased heart rate, or death if used with certain drugs, and may reduce the effects of certain drugs used to treat cancer and other diseases. The U.S. Food and Drug Administration has banned the sale of dietary supplements that contain ma huang. Also called ephedra.

macroglobulinemia A condition in which the blood contains high levels of large proteins and is too thick to flow through small blood vessels. One type is Waldenström's macroglobulinemia, which is a type of cancer.

macrophage A type of white blood cell that surrounds and kills microorganisms, removes dead cells and stimulates the action of other immune system cells.

mafosfamide A form of cyclophosphamide that can be administered as an intrathecal infusion. Mafosfamide is being studied as an anticancer drug. It belongs to the family of drugs called alkylating agents.

MAGE-3 A gene found in some types of tumors.

magnesium In medicine, a mineral used by the body to help maintain muscles, nerves and bones. It is also used in energy metabolism and protein synthesis.

magnesium sulfate A drug used to treat pre-eclampsia and eclampsia (serious complications of pregnancy). Magnesium sulfate is also being studied for its ability to prevent the toxic side effects of certain drugs used to treat colorectal cancer. It is a type of anticonvulsant agent.

magnetic resonance imaging 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 computed tomography (CT) or X-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called MRI, nuclear magnetic resonance imaging and NMRI.

magnetic resonance perfusion imaging A special type of magnetic resonance imaging (MRI) that uses an injected dye in order to see blood flow through tissues. Also called perfusion magnetic resonance imaging.

magnetic resonance spectroscopic imaging MRSI. A noninvasive imaging method that provides information about cellular activity (metabolic information). It is used along with magnetic resonance imaging (MRI) which provides information about the shape and size of the tumor (spatial information). Also called 1H-nuclear magnetic resonance spectroscopic imaging and proton magnetic resonance spectroscopic imaging.

magnetic-targeted carrier A tiny bead made from particles of iron and carbon that can be attached to an anticancer drug. A magnet applied from outside the body then can direct the drug to the tumor site. This can keep a larger dose of the drug at the tumor site for a longer period of time, and help protect healthy tissue from the side effects of chemotherapy.

maidenhair tree A tree native to China. Substances taken from the leaves and seeds have been used in some cultures to treat certain medical problems. Maidenhair tree has been studied in the prevention and treatment of Alzheimer’s disease, dementia, certain blood vessel diseases and memory loss. It may cause bleeding or high blood pressure when used with certain drugs. Also called ginkgo and ginkgo biloba.

mainstream medicine A system in which medical doctors and other healthcare professionals (such as nurses, pharmacists and therapists) treat symptoms and diseases using drugs, radiation, or surgery. Also called conventional medicine, Western medicine, orthodox medicine, biomedicine and allopathic medicine.

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.

malabsorption syndrome A group of symptoms such as gas, bloating, abdominal pain, and diarrhea resulting from the body's inability to properly absorb nutrients.

male breast cancer Cancer that forms in tissues of the breast in men. Most male breast cancer begins in cells lining the ducts. It is very rare and usually affects older men.

malignancy A cancerous tumor that can invade and destroy nearby tissue and spread to other parts of the body.

malignant Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

malignant ascites A condition in which fluid containing cancer cells collects in the abdomen.

malignant ectomesenchymoma A rare, fast-growing tumor of the nervous system or soft tissue that occurs in children and young adults. Malignant ectomesenchymomas may form in the head and neck, abdomen, perineum, scrotum or limbs. Also called ectomesenchymoma.

malignant fibrous cytoma A soft tissue sarcoma that usually occurs in the limbs, most commonly the legs, and may also occur in the abdomen. Also called malignant fibrous histiocytoma.

malignant fibrous histiocytoma A soft tissue sarcoma that usually occurs in the limbs, most commonly the legs, and may also occur in the abdomen. Also called malignant fibrous cytoma.

malignant meningioma A rare, fast-growing tumor that forms in one of the inner layers of the meninges (thin layers of tissue that cover and protect the brain and spinal cord). Malignant meningioma often spreads to other areas of the body.

malignant mesothelioma A rare type of cancer in which malignant cells are found in the sac lining the chest or abdomen. Exposure to airborne asbestos particles increases one's risk of developing malignant mesothelioma.

malignant mixed Müllerian tumor MMMT. A rare type of tumor that is a mixture of carcinoma and sarcoma cells. MMMT usually occurs in the uterus. Also called MMMT.

malignant peripheral nerve sheath tumor MPNST. A type of soft tissue sarcoma that develops in cells that form a protective sheath (covering) around peripheral nerves, which are nerves that are outside of the central nervous system (brain and spinal cord). Also called MPNST.

malnutrition A disorder caused by a lack of proper nutrition or an inability to absorb nutrients from food.

malondialdehyde A byproduct of lipid (fat) metabolism in the body. It is also found in many foods and can be present in high amounts in rancid food.

MALT lymphoma Mucosa-associated lymphoid tissue lymphoma. A type of cancer that arises in cells in mucosal tissue that are involved in antibody production. Also called mucosa-associated lymphoid tissue lymphoma.

mammary Having to do with the breast.

mammary dysplasia A common condition marked by benign (noncancerous) changes in breast tissue. These changes may include irregular lumps or cysts, breast discomfort, sensitive nipples and itching. These symptoms may change throughout the menstrual cycle and usually stop after menopause. Also called benign breast disease, fibrocystic breast disease and fibrocystic breast changes.

mammary gland Glandular organ located on the chest. The mammary gland is made up of connective tissue, fat and breast tissue that contains the glands that can make milk. Also called breast.

mammogram An X-ray of the breast.

mammography The use of X-rays to create a picture of the breast.

Mammotome A device that uses a computer-guided probe to perform breast biopsies. A Mammotome biopsy can be done on an outpatient basis with a local anesthetic, removes only a small amount of healthy tissue and doesn’t require sutures (stitches) because the incision is very small.

mannitol A drug used to decrease swelling of the brain and to treat kidney failure. Mannitol can also be used to open the blood-brain barrier, which allows anticancer medicines to enter the brain and treat brain tumors.

mantle cell lymphoma An aggressive (fast-growing) type of B-cell non-Hodgkin’s lymphoma that usually occurs in middle-aged or older adults. It is marked by small- to medium-size cancer cells that may be in the lymph nodes, spleen, bone marrow, blood and gastrointestinal system.

mantle field The area of the neck, chest and lymph nodes in the armpit that are exposed to radiation.

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.

marijuana A type of plant. Extracts of marijuana are being studied for their ability to control severe nausea and vomiting caused by chemotherapy and/or opioid drugs such as morphine.

marimastat An anticancer drug that belongs to the family of drugs called angiogenesis inhibitors. Marimastat is a matrix metalloproteinase inhibitor.

marker A diagnostic indication that disease may develop.

MART-1 antigen A 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. Vaccines made using the MART-1 antigen are being studied in the treatment of advanced melanoma. Also called Melan-A protein.

masoprocol A drug put on the skin to treat growths caused by sun exposure. A form of nordihydroguaiaretic acid that is taken by mouth is being studied in the treatment of prostate cancer. Nordihydroguaiaretic acid is an antioxidant, and it may block certain enzymes needed for tumor growth. Also called nordihydroguaiaretic acid, NDGA and Actinex.

massage therapy A treatment in which the soft tissues of the body are kneaded, rubbed, tapped, and stroked. Massage therapy may help people relax, relieve stress and pain, lower blood pressure and improve circulation. It is being studied in the treatment of cancer symptoms such as lack of energy, pain, swelling and depression.

mast cell A type of white blood cell.

mast cell tumor A growth or lump of mast cells (a type of white blood cell). Mast cell tumors can involve the skin, subcutaneous tissue and muscle tissue. Also called mastocytoma.

mastectomy Surgery to remove the breast (or as much of the breast tissue as possible).

mastocytoma A growth or lump of mast cells (a type of white blood cell). Mast cell tumors can involve the skin, subcutaneous tissue and muscle tissue. Also called mast cell tumor.

matrix metalloproteinase A member of a group of enzymes that can break down proteins, such as collagen, that are normally found in the spaces between cells in tissues (i.e., extracellular matrix proteins). Because these enzymes need zinc or calcium atoms to work properly, they are called metalloproteinases. Matrix metalloproteinases are involved in wound healing, angiogenesis and tumor cell metastasis.

mature T-cell lymphoma One of a group of aggressive (fast-growing) non-Hodgkin’s lymphomas that begin in mature T lymphocytes (T cells that have matured in the thymus gland and gone to other lymphatic sites in the body, including lymph nodes, bone marrow and spleen.) Also called peripheral T-cell lymphoma.

mature teratoma A type of benign (noncancerous) germ cell tumor (type of tumor that begins in the cells that give rise to sperm or eggs) that often contains several different types of tissue such as hair, muscle and bone. Also called a dermoid cyst.

matuzumab A monoclonal antibody that is being studied in the treatment of some types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to cancer cells. Matuzumab binds to the epithelial growth factor receptor (EGFR) on tumor cells and blocks growth signals. Also called EMD 72000.

maximum inspiratory pressure test MIP test. A test that measures the strength of the muscles used in breathing. A person inhales and exhales through a device called a manometer, and the pressures are recorded by a computer. Also called MIP test.

maytansinoid DM4-conjugated humanized monoclonal antibody huC242 A substance being studied in the treatment of some types of cancer. It is made by linking the monoclonal antibody huC242 to a toxic substance called maytansinoid DM4. The monoclonal antibody locates and binds to the surfaces of cancer cells and the maytansinoid DM4 enters the cells and blocks their growth. It is a type of immunotoxin. Also called huC242-DM4.

MDL 101,731 A drug that belongs to a family of drugs called ribonucleotide reductase inhibitors.

MDX-010 A monoclonal antibody being studied in the treatment of certain types of cancer. MDX-010 is made in the laboratory and binds to the molecule CTLA-4 on T cells (a type of white blood cell). MDX-010 may block CTLA-4 and help the immune system kill cancer cells. Also called ipilimumab.

MDX-060 A monoclonal antibody that is being studied in the treatment of some lymphomas. Monoclonal antibodies are produced in the laboratory and can locate and bind to cancer cells.

mean A statistics term. The average value in a set of measurements. The mean is the sum of a set of numbers divided by how many numbers are in the set.

mean survival time The average time that patients in a clinical study remained alive. The time is measured beginning either at diagnosis or the start of treatment.

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

mechlorethamine A drug used to treat some types of cancer and some precancerous skin conditions. It belongs to the family of drugs called alkylating agents. Also called Mustargen.

medial supraclavicular lymph node A lymph node located above the collar bone and between the center of the body and a line drawn through the nipple to the shoulder.

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.

median umbilical ligament A fibrous cord that connects the urinary bladder to the umbilicus (navel). The median umbilical ligament is formed as the allantoic stalk during fetal development and lasts through life. Also called urachus.

mediastinal pleura The thin membrane that lines the chest cavity in the area between the lungs.

mediastinoscope A thin, tube-like instrument used to examine the tissues and lymph nodes in the area between the lungs. These tissues include the heart and its large blood vessels, trachea, esophagus, and bronchi. The mediastinoscope has a light and a lens for viewing and may also have a tool to remove tissue. It is inserted into the chest through a cut above the breastbone.

mediastinoscopy A procedure in which a mediastinoscope is used to examine the organs in the area between the lungs and nearby lymph nodes. A mediastinoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. The mediastinoscope is inserted into the chest through an incision above the breastbone. This procedure is usually done to get a tissue sample from the lymph nodes on the right side of the chest.

mediastinum The area between the lungs. The organs in this area include the heart and its large blood vessels, the trachea, the esophagus, the bronchi and lymph nodes.

medical castration Refers to the use of drugs to suppress the function of the ovaries or testicles.

medical device An instrument, tool, machine, test kit or implant that is used to prevent, diagnose or treat disease or other conditions. Medical devices range from tongue depressors to heart pacemakers and medical imaging equipment.

medical nutrition therapy Treatment based on nutrition. It includes checking a person’s nutrition status, and giving the right foods or nutrients to treat conditions such as those caused by diabetes, heart disease and cancer. It may involve simple changes in a person’s diet, or intravenous or tube feeding. Medical nutrition therapy may help patients recover more quickly and spend less time in the hospital. Also called nutrition therapy.

medical oncologist A doctor who specializes in diagnosing and treating cancer using chemotherapy, hormonal therapy and biological therapy. A medical oncologist often is the main health care provider for someone who has cancer. A medical oncologist also gives supportive care and may coordinate treatment given by other specialists.

medication A legal drug that is used to prevent, treat or relieve symptoms of a disease or abnormal condition. Also called medicine.

medicine A legal drug that is used to prevent, treat, or relieve symptoms of a disease or abnormal condition. Also called medication.

medroxyprogesterone A hormonal anticancer drug that is also used in cancer prevention. It belongs to the family of drugs called progestins.

medroxyprogesterone acetate A drug used to prevent endometrial cancer. It is also used to treat menstrual disorders and as a form of birth control. It is a form of the female hormone progesterone and belongs to the family of drugs called progestins.

medullary breast carcinoma A rare type of breast cancer that often can be treated successfully. It is marked by lymphocytes (a type of white blood cell) in and around the tumor that can be seen when viewed under a microscope.

medullary thyroid cancer Cancer that develops in C cells of the thyroid. The C cells make a hormone (calcitonin) that helps maintain a healthy level of calcium in the blood.

medulloblastoma 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 uses electricity to form a stream of fast-moving subatomic particles. This creates high-energy radiation that may be used to treat cancer. Also called MeV linear accelerator, linear accelerator and linac.

Megace A drug used to block estrogen and suppress the effects of estrogen and androgens. It is used to treat breast and endometrial cancer, and is being studied in the treatment of other types of cancer. It is also used to improve appetite in patients with cancer. Megace belongs to the group of hormones called progestins. Also called megestrol.

megestrol A drug used to block estrogen and suppress the effects of estrogen and androgens. It is used to treat breast and endometrial cancer, and is being studied in the treatment of other types of cancer. It is also used to improve appetite in patients with cancer. Megestrol belongs to the group of hormones called progestins. Also called Megace.

meiosis A special form of cell division in which each daughter cell receives half the amount of DNA as the parent cell. Meiosis occurs during formation of egg and sperm cells in mammals.

Melan-A protein A 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. Vaccines made using the Melan-A protein are being studied in the treatment of advanced melanoma. Also called MART-1 antigen.

melanin The substance that gives color to skin and eyes.

melanocyte A cell in the skin and eyes that produces and contains the pigment called melanin.

melanoma A form of skin cancer that begins in melanocytes (the cells that make the pigment melanin). Melanoma usually begins in a mole.

melanoma in situ Cancer is found in the epidermis (outer layer of the skin) only. Also called stage 0 melanoma.

melanoma vaccine A cancer vaccine prepared from human melanoma cancer cells. It can be used alone or with other therapy in treating melanoma.

melatonin A hormone made by the pineal gland (tiny organ near the center of the brain). Melatonin helps control the body’s sleep cycle, and is an antioxidant. It is also made in the laboratory and sold as a supplement.

melphalan A drug that is used to treat multiple myeloma and ovarian epithelial cancer and is being studied in the treatment of other types of cancer. It belongs to the family of drugs called alkylating agents. Also called Alkeran.

membrane A very thin layer of tissue that covers a surface.

MEN-10755 An anticancer drug that belongs to the family of drugs called antitumor antibiotics.

MEN1 syndrome Multiple endocrine neoplasia type 1 syndrome. A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas. These tumors (usually benign) cause the glands to secrete high levels of hormones, which can lead to other medical problems, such as kidney stones, fertility problems, and severe ulcers. In some cases, tumors inside the pancreas can become cancerous. Also called multiple endocrine neoplasia type 1 syndrome, multiple endocrine adenomatosis and Wermer's syndrome.

meningeal Having to do with the meninges (three thin layers of tissue that cover and protect the brain and spinal cord).

meningeal metastasis Cancer that has spread from the original (primary) tumor to the meninges (three thin layers of tissue that cover and protect the brain and spinal cord).

meninges The three thin layers of tissue that cover and protect the brain and spinal cord.

meningioma A type of slow-growing tumor that forms in the meninges (thin layers of tissue that cover and protect the brain and spinal cord). Meningiomas usually occur in adults.

meningitis Inflammation of the meninges (three thin layers of tissue that cover and protect the brain and spinal cord). Meningitis is usually caused by a bacterial or viral infection, but sometimes is caused by cancer, drug allergies or inflammatory diseases.

menopausal hormone therapy Hormones (estrogen, progesterone, or both) given to women after menopause to replace the hormones no longer produced by the ovaries. Also called hormone replacement therapy and 2007-03-16.

menopause 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. Also called change of life.

menorrhagia Abnormally heavy menstrual bleeding.

menstrual cycle The monthly cycle of hormonal changes from the beginning of one menstrual period to the beginning of the next.

menstrual period The periodic discharge of blood and tissue from the uterus. From puberty until menopause, menstruation occurs about every 28 days, but does not occur during pregnancy.

menstruation Periodic discharge of blood and tissue from the uterus. From puberty until menopause, menstruation occurs about every 28 days when a woman is not pregnant.

mental health A 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 events, think clearly, be responsible, meet challenges and have good relationships with others.

mental health counselor A specialist who can talk with patients and their families about emotional and personal matters, and can help them make decisions.

meperidine A morphine-like drug used to relieve medium to severe pain. It belongs to the family of drugs called opioid analgesics and may be habit-forming. Also called Demerol.

mercaptopurine A drug used to treat acute lymphatic leukemia. It belongs to the family of drugs called antimetabolites. Also called Purinethol.

mercury A 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 ingredient in some homeopathic medicines and in very small amounts as a preservative in viral vaccines.

mercy killing An 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. Also called euthanasia.

meridian In traditional Chinese medicine, one of 20 channels that form a network through which qi (the body's vital energy) flows and that connect the body’s acupuncture sites.

Merkel cell cancer A rare type of cancer that forms on or just beneath the skin. Merkel cell cancer is divided into three types called trabecular, intermediate and small cell.

mesenchymal Refers to cells that develop into connective tissue, blood vessels, and lymphatic tissue.

mesenteric membrane The peritoneal membrane that attaches the intestines to the abdominal wall near the back.

mesna A drug that helps protect the kidneys and bladder from the toxic effects of anticancer drugs such as ifosfamide and cyclophosphamide.

mesonephroma A rare type of tumor, usually of the female genital tract, in which the inside of the cells looks clear when viewed under a microscope. Also called clear cell carcinoma and clear cell adenocarcinoma.

mesothelioma A benign (noncancerous) or malignant (cancerous) tumor affecting the lining of the chest or abdomen. Exposure to asbestos particles in the air increases the risk of developing malignant mesothelioma.

metabolic 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 materials needed for important life processes).

metabolic acidosis A condition in which the blood is too acidic. It may be caused by severe illness or sepsis (bacteria in the bloodstream).

metabolic disorder A condition in which normal metabolic processes are disrupted, usually because of a missing enzyme.

metabolic therapy Treatment to correct changes in metabolism that can be caused by disease.

metabolic type In alternative medicine, a theory that people fall into one of three groups (protein, carb, or mixed type) based on the main type of food that their bodies need to stay healthy.

metabolism The total of all chemical changes that take place in a cell or an organism. These changes produce energy and basic materials needed for important life processes.

metabolite Any substance involved in metabolism (the chemical changes that take place in a cell or organism to make the energy and basic materials important in life processes). Metabolite is often used to describe the products left after a drug is used by the body.

metallic Having to do with metal. Some cancer treatments may change the sense of taste and cause foods to have a metallic taste.

metaplasia A change of cells to a form that does not normally occur in the tissue in which it is found.

metaplastic carcinoma A 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 changing to resemble a cell of the stomach). In some cases, metaplastic changes alone may mean there is an increased chance of cancer developing at the site.

metastasectomy Surgery to remove one or more metastases (tumors formed from cells that have spread from the primary tumor). When all metastases are removed, it is called a complete metastasectomy.

metastasis 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.

metastasize 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 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.

metasynchronous Occurring at nearly the same time.

meteorism Swelling of the abdomen caused by gas in the intestines or peritoneal cavity. Also called tympanites.

methadone A morphine-like drug used to treat severe pain and to prevent withdrawal symptoms in patients who are addicted to heroin or other opiates. It may also be used to treat severe coughing in lung cancer patients. Methadone belongs to the family of drugs called opioid analgesics.

methodology In medicine, the rules and procedures for doing research and evaluating results.

methotrexate A drug used to treat some types of cancers, including breast, head and neck, lung, blood, and bone, and other disorders. It belongs to the family of drugs called antimetabolites. Also called amethopterin.

methoxsalen A drug used together with UV light to treat psoriasis, vitiligo, and skin nodules of cutaneous T-cell lymphoma. It is also being studied in the treatment of graft-versus-host disease. It belongs to the family of drugs called psoralens and furocoumarins.

methoxypolyethylene glycol epoetin beta A substance that is being studied in the treatment of anemia in patients who are receiving chemotherapy. It is a form of erythropoietin (a substance produced in the kidneys that stimulates the production of red blood cells) that has been changed in the laboratory. Also called Ro 50-3821.

methyl-5-aminolevulinate A drug used in photodynamic therapy; it is absorbed by tumor cells and, when exposed to light, becomes active and kills the cancer cells.

methylphenidate A drug that is a central nervous system stimulant.

methylprednisolone A corticosteroid hormone replacement.

metoclopramide A drug that increases the motility (movements and contractions) of the stomach and upper intestine. It is used to treat certain stomach problems and nausea and vomiting caused by chemotherapy. It belongs to the families of drugs called antiemetics and motility agents. Also called Reglan.

metronidazole A drug that is used to treat infection and is being studied in the treatment of cancer. It belongs to the families of drugs called antibacterials, antiprotozoals and anthelmintics. Also called Flagyl.

metronomic therapy Continuous or frequent treatment with low doses of anticancer drugs, often given with other methods of therapy.

MeV linear accelerator Mega-voltage linear accelerator. A 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. Also called mega-voltage linear accelerator, linear accelerator and linac.

Mexican 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, Indian valerian, Pacific valerian, garden heliotrope, Valeriana officinalis and Valerianae radix.

MG98 An anticancer drug that belongs to the family of drugs called antisense compounds. These drugs interfere with production of certain proteins in the cell.

MGUS Monoclonal gammopathy of undetermined significance. A benign condition in which there is a high level of a protein called M protein in the blood. Patients with MGUS are at an increased risk of developing cancer. Also called monoclonal gammopathy of undetermined significance.

microcalcification A tiny deposit of calcium in the breast that cannot be felt but can be detected on a mammogram. A cluster of these very small specks of calcium may indicate that cancer is present.

microgram One millionth of a gram.

micrometastasis 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.

micro-molar A concentration of 1/1,000,000 (one millionth) molecular weight per liter (mol/L).

micronutrient A substance the body needs in tiny amounts to grow and stay healthy. Examples are vitamins and minerals.

microorganism An organism that can be seen only through a microscope. Microorganisms include bacteria, protozoa, algae and fungi. Although viruses are not considered living organisms, they are sometimes classified as microorganisms.

microsatellite A short sequence of DNA, usually 1 to 4 basepairs (a unit of DNA), that is repeated together in a row along the DNA molecule. There is variation from person to person in the number of repeats. There are hundreds of places in human DNA that contain microsatellites.

microsatellite instability MSI. A change that occurs in the DNA of certain cells (such as tumor cells) in which the number of repeats of microsatellites (short, repeated sequences of DNA) is different than the number of repeats that was in the DNA when it was inherited. The cause of MSI may be a defect in the ability to repair mistakes made when DNA is copied in the cell. Also called MSI.

microscopic Too small to be seen without a microscope.

microstaging A technique used to help determine the stage (extent) of melanoma and certain squamous cell cancers. A sample of skin that contains tumor tissue is examined under a microscope to find out how thick the tumor is and/or how deeply the tumor has grown into the skin or connective tissues.

microwave acupuncture A type of acupuncture in which a microwave device is attached to an acupuncture needle to give microwave radiation at an acupuncture point.

microwave therapy 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 thermotherapy.

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.

midostaurin A substance that is being studied in the treatment of leukemia. It belongs to the family of drugs called protein kinase inhibitors. Also called N-benzoyl-staurosporine and PKC412.

Mifeprex A drug used to end early pregnancies. It is also being studied in the treatment of some types of cancer and other conditions. Mifeprex blocks the action of progesterone, a hormone that helps some cancers grow. It is a type of antiprogesterone. Also called mifepristone and RU 486.

mifepristone A drug used to end early pregnancies. It is also being studied in the treatment of some types of cancer and other conditions. Mifepristone blocks the action of progesterone, a hormone that helps some cancers grow. It is a type of antiprogesterone. Also called RU 486 and Mifeprex.

milk thistle A plant that has been used in some cultures to treat certain medical problems, including stomach, liver, and gallbladder disorders. The active extract of milk thistle seeds is called silymarin. It is being studied in the prevention of liver damage caused by some cancer treatments. Also called Silybum marianum.

milligram A measure of weight. A milligram is approximately 450,000 times smaller than a pound and 28,000 times smaller than an ounce.

milliliter A measure of volume for a liquid. A milliliter is approximately 950 times smaller than a quart and 30 times smaller than a fluid ounce. A milliliter of liquid and a cubic centimeter (cc) of liquid are the same.

millimeter A measure of length in the metric system. A millimeter is one thousandth of a meter. There are 25 millimeters in an inch.

mind/body exercise A form of exercise that combines body movement with mental focus and controlled breathing to improve strength, balance, flexibility and overall health. Examples of mind/body exercises are yoga, tai chi and qigong.

mindfulness relaxation A type of meditation based on the concept of being “mindful,” or having increased awareness, of the present. It uses breathing methods, guided imagery and other practices to relax the body and mind and help reduce stress.

mineral A nutrient required to maintain health.

mineral oil A type of oil that is made from petroleum (mixture of oily liquids found in the earth). Mineral oil is used in laxatives, lubricants, creams and lotions.

MIP test Maximum inspiratory pressure test. A test that measures the strength of the muscles used in breathing. A person inhales and exhales through a device called a manometer, and the pressures are recorded by a computer. Also called maximum inspiratory pressure test.

Miraluma test A type of breast imaging test that is used to detect cancer cells in the breasts of some women who have had abnormal mammograms, or who have dense breast tissue. The Miraluma test is not used for screening, or in place of a mammogram. In this test, a woman receives an injection of a small amount of a radioactive substance called technetium 99, which is taken up by cancer cells, and a gamma camera is used to take pictures of the breasts. Also called scintimammography and sestamibi breast imaging.

mirtazapine A drug used to treat depression. It belongs to the family of drugs called antidepressant agents. Also called Remeron.

misoprostol A radioprotective agent that belongs to the family of drugs called prostaglandins.

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

mistletoe lectin A substance that comes from the mistletoe plant and that is being studied as a treatment for cancer. A lectin is a complex molecule that has both protein and sugars. Lectins are able to bind to the outside of a cell and cause biochemical changes in it. Lectins are made by both animals and plants.

Mithracin A drug used to treat some types of testicular cancer, hypercalcemia (abnormally high levels of calcium in the blood), and hypercalciuria (abnormally high levels of calcium in the urine). It belongs to the families of drugs called antineoplastics and antibiotics. Also called plicamycin.

mitigate To make milder or less painful.

mitochondria Small structures in a cell that are found in the cytoplasm (fluid that surrounds the cell nucleus). Mitochondria make most of the energy for the cell and have their own genetic material that is different from the genetic material found in the nucleus. Many diseases are caused by mutations (changes) in DNA of the mitochondria.

mitolactol An anticancer drug that belongs to the family of drugs called alkylating agents.

mitomycin An anticancer drug that belongs to the family of drugs called antitumor antibiotics.

mitosis The process of division of somatic cells in which each daughter cell receives the same amount of DNA as the parent cell.

mitotane An anticancer drug used in treating adrenocortical cancer and ACTH-producing pituitary tumors (Cushing's disease).

mitotic activity Having to do with the presence of dividing (proliferating) cells. Cancerous tissue generally has more mitotic activity than normal tissues.

mitotic index In a population of cells, the ratio of the number of cells undergoing mitosis (cell division) to the number of cells not undergoing mitosis.

mitotic inhibitor A type of drug that blocks cell growth by stopping cell division. Mitotic inhibitors are used to treat cancer. Also called antimicrotubule agent, antimitotic agent, taxane and vinca alkaloid.

mitoxantrone A drug used to treat advanced prostate cancer that does not respond to hormones, adult acute nonlymphocytic leukemia, and advanced or chronic multiple sclerosis. It is also being studied in the treatment of other cancers. It belongs to the family of drugs called antitumor antibiotics. Also called Novantrone.

mivobulin isethionate An anticancer drug that belongs to the family of drugs called mitotic inhibitors. Also called CI-980.

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

MMMT Malignant mixed Müllerian tumor. A rare type of tumor that is a mixture of carcinoma and sarcoma cells. MMMT usually occurs in the uterus. Also called malignant mixed Müllerian tumor.

modafinil A drug that is being studied as a treatment for fatigue in patients with cancer. It belongs to the family of drugs called stimulants.

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

modified radical mastectomy Surgery for breast cancer in which the breast, most or all of the lymph nodes under the arm, and the lining over the chest muscles are removed. Sometimes the surgeon also removes part of the chest wall muscles.

modulate To adjust, or change.

Mohs micrographic surgery A surgical procedure used to treat skin cancer. Individual layers of cancerous tissue are removed and examined under a microscope one at a time until all cancerous tissue has been removed. Also called Mohs surgery.

Mohs surgery A surgical procedure used to treat skin cancer. Individual layers of cancerous tissue are removed and examined under a microscope one at a time until all cancerous tissue has been removed. Also called Mohs micrographic surgery.

molar pregnancy A condition in women of childbearing age in which grape-like cysts grow in the uterus after conception (fertilization of an egg by a sperm). Molar pregnancies may change into a type of cancer called choriocarcinoma or gestational trophoblastic tumor. Also called hydatidiform mole.

mold A form of fungus. Some molds can cause disease in humans.

mole In medicine, a benign growth on the skin that is formed by a cluster of melanocytes (cells that make the pigment melanin). Moles are usually dark, and may be raised from the skin.

molecular mass The sum of the atomic masses of all atoms in a molecule, based on a scale in which the atomic masses of hydrogen, carbon, nitrogen, and oxygen are 1, 12, 14, and 16, respectively. For example, the molecular mass of water, which has two atoms of hydrogen and one atom of oxygen, is 18 (i.e., 2 + 16).

molecular medicine A branch of medicine that develops ways to diagnose and treat disease by understanding the way genes, proteins and other cellular molecules work. Molecular medicine is based on research that shows how certain genes, molecules and cellular functions may become abnormal in diseases such as cancer.

molecular risk assessment A procedure in which biomarkers (for example, biological molecules or changes in tumor cell DNA) are used to estimate a person’s risk for developing cancer. Specific biomarkers may be linked to particular types of cancer.

molecularly targeted therapy In cancer treatment, substances that kill cancer cells by targeting key molecules involved in cancer cell growth.

molecule The smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms. If they contain more than one atom, the atoms can be the same (an oxygen molecule has two oxygen atoms) or different (a water molecule has two hydrogen atoms and one oxygen atom). Biological molecules, such as proteins and DNA, can be made up of many thousands of atoms.

monitor In medicine, to regularly watch and check a person or condition to see if there is any change. Also refers to a device that records and/or displays patient data, such as for an electrocardiogram (EKG).

monoclonal antibody A type of protein made in the laboratory that can locate and bind to substances in the body and on the surface of cancer cells. There are many kinds of monoclonal antibodies; each one is made to find a different substance. Monoclonal antibodies are being used to treat some types of cancer and are being studied in the treatment of other types. They can be used alone or to carry drugs, toxins or radioactive materials directly to a tumor.

monoclonal gammopathy of undetermined significance MGUS. A benign condition in which there is a high level of a protein called M protein in the blood. Patients with MGUS are at an increased risk of developing cancer. Also called MGUS.

monoclonal protein An antibody or part of an antibody found in unusually large amounts in the blood or urine of people with multiple myeloma and other types of plasma cell tumors. Also called M protein.

monocyte A type of white blood cell.

Montanide ISA-51 A drug used in vaccine therapy to stimulate the immune system.

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.

morphine A narcotic drug used in the treatment of pain.

morphology The science of the form and structure of organisms (plants, animals and other forms of life).

mortality The state of being mortal (destined to die). Mortality also refers to the death rate, or the number of deaths in a certain group of people in a certain period of time. Mortality may be reported for people who have a certain disease, live in one area of the country, or who are of a certain gender, age or ethnic group.

motexafin gadolinium A substance that is being studied in the treatment of cancer. It may make tumor cells more sensitive to radiation therapy, improve tumor images using magnetic resonance imaging (MRI), and kill cancer cells. It belongs to the family of drugs called metalloporphyrin complexes. Also called gadolinium texaphyrin.

motexafin lutetium A substance that is being studied in the treatment of cancer using photodynamic therapy. It belongs to the family of drugs called metallotexaphyrins. Also called lutetium texaphyrin.

motor In medicine, having to do with the movement of body parts.

moxibustion In traditional Chinese medicine, a type of heat therapy in which an herb is burned on or above the skin to warm and stimulate an acupuncture point or affected area.

moxifloxacin A drug that is used to treat bacterial infections. It belongs to the family of drugs called fluoroquinolones. Also called Avelox or moxifloxacin hydrochloride.

moxifloxacin hydrochloride A drug that is used to treat bacterial infections. It belongs to the family of drugs called fluoroquinolones. Also called moxifloxacin or Avelox.

MPNST Malignant peripheral nerve sheath tumor. A type of soft tissue sarcoma that develops in cells that form a protective sheath (covering) around peripheral nerves, which are nerves that are outside of the central nervous system (brain and spinal cord). Also called malignant peripheral nerve sheath tumor.

MRI Magnetic resonance imaging. 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 computed tomography (CT) or X-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, nuclear magnetic resonance imaging and NMRI.

MRSI Magnetic resonance spectroscopic imaging. A noninvasive imaging method that provides information about cellular activity (metabolic information). It is used along with magnetic resonance imaging (MRI) which provides information about the shape and size of the tumor (spacial information).

MSI Microsatellite instability. A change that occurs in the DNA of certain cells (such as tumor cells) in which the number of repeats of microsatellites (short, repeated sequences of DNA) is different than the number of repeats that was in the DNA when it was inherited. The cause of MSI may be a defect in the ability to repair mistakes made when DNA is copied in the cell. Also called microsatellite instability.

mucin/peptide A protein/sugar compound made by some cancer cells.

mucinous Containing or resembling mucin, the main compound in mucus.

mucinous carcinoma A type of cancer that begins in cells that line certain internal organs and produce mucin (the main component of mucus).

mucosa The moist, inner lining of some organs and body cavities (such as the nose, mouth, lungs, and stomach). Glands in the mucosa make mucus (a thick, slippery fluid). Also called mucous membrane.

mucosa-associated lymphoid tissue lymphoma MALT lymphoma. A type of cancer that arises in cells in mucosal tissue that are involved in antibody production. Also called MALT lymphoma.

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

mucous membrane The moist, inner lining of some organs and body cavities (such as the nose, mouth, lungs and stomach). Glands in the mucous membrane make mucus (a thick, slippery fluid). Also called mucosa.

mucus A thick, slippery fluid made by the membranes that line certain organs of the body, including the nose, mouth, throat, and vagina.

muJ591 A type of monoclonal antibody used in cancer detection or therapy. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

Mullerian tumor A rare cancer of the uterus, ovary, or fallopian tubes.

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

multicentric breast cancer Breast cancer in which there is more than one tumor, all of which have formed separately from one another. The tumors are likely to be in different quadrants (sections) of the breast. Multicentric breast cancers are rare.

multidisciplinary In medicine, a term used to describe a treatment planning approach or team that includes a number of doctors and other health care professionals who are experts in different specialties (disciplines). In cancer treatment, the primary disciplines are medical oncology (treatment with drugs), surgical oncology (treatment with surgery), and radiation oncology (treatment with radiation).

multidisciplinary opinion 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 multidisciplinary opinion 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 tumor board review.

multidrug resistance Adaptation of tumor cells to anticancer drugs in ways that make the drugs less effective.

multidrug resistance inhibition Treatment used to make cancer cells less resistant to anticancer drugs.

multifocal breast cancer Breast cancer in which there is more than one tumor, all of which have arisen from one original tumor. The tumors are likely to be in the same quadrant (section) of the breast.

multimodality treatment Therapy that combines more than one method of treatment.

multiple endocrine adenomatosis A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas. These tumors (usually benign) cause the glands to secrete high levels of hormones, which can lead to other medical problems, such as kidney stones, fertility problems, and severe ulcers. In some cases, tumors inside the pancreas can become cancerous. Also called multiple endocrine neoplasia type 1 syndrome, MEN1 syndrome and Wermer's syndrome.

multiple endocrine neoplasia syndrome An inherited tendency to develop thyroid cancer and other cancers of the endocrine system. The altered gene can be detected with a blood test.

multiple endocrine neoplasia type 1 syndrome MEN1 syndrome. A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas. These tumors (usually benign) cause the glands to secrete high levels of hormones, which can lead to other medical problems, such as kidney stones, fertility problems and severe ulcers. In some cases, tumors inside the pancreas can become cancerous. Also called MEN1 syndrome, multiple endocrine adenomatosis and Wermer's syndrome.

multiple myeloma A type of cancer that begins in plasma cells (white blood cells that produce antibodies). Also called Kahler’s disease, myelomatosis or plasma cell myeloma.

multiple sclerosis A disorder of the central nervous system marked by weakness, numbness, a loss of muscle coordination, and problems with vision, speech, and bladder control. Multiple sclerosis is thought to be an autoimmune disease in which the body's immune system destroys myelin. Myelin is a substance that contains both protein and fat (lipid), serving as a nerve insulator and helping in the transmission of nerve signals.

multiplicity A large number or variety.

mung bean A type of bean grown in warm climates, usually for its seed and for bean sprouts. Mung bean may have anticancer effects.

muromonab-CD3 A type of monoclonal antibody used in cancer detection or therapy. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

muscle wasting A weakening, shrinking, and loss of muscle caused by disease or lack of use. Muscle wasting decreases strength and the ability to move.

musculoskeletal Having to do with muscles, bones, and cartilage.

Mustargen A drug used to treat some types of cancer and some precancerous skin conditions. It belongs to the family of drugs called alkylating agents. Also called mechlorethamine.

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 Pain in a muscle or group of muscles.

myasthenia gravis A disease in which antibodies made by a person’s immune system prevent certain nerve-muscle interactions. It causes weakness in the arms and legs, vision problems, and drooping eyelids or head. It may also cause paralysis and problems with swallowing, talking, climbing stairs, lifting things and getting up from a sitting position. The muscle weakness gets worse during activity, and improves after periods of rest.

mycophenolate mofetil A drug that is being studied for its effectiveness in preventing graft-versus-host disease and autoimmune disorders.

mycosis fungoides A type of non-Hodgkin's lymphoma that first appears on the skin and can spread to the lymph nodes or other organs such as the spleen, liver, or lungs.

mycosis fungoides plaque In mycosis fungoides, an area of skin that is thickened, raised, red, scaly and itchy.

mycostatin A drug that treats infections caused by fungi.

myelin The fatty substance that covers and protects nerves.

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

myelodysplasia Abnormal bone marrow cells that may lead to myelogenous leukemia.

myelodysplastic syndromes A group of diseases in which the bone marrow does not make enough healthy blood cells. Also called preleukemia and smoldering leukemia.

myelofibrosis A disorder in which the bone marrow is replaced by fibrous tissue.

myelogenous Having to do with, produced by, or resembling the bone marrow. Sometimes used as a synonym for myeloid; for example, acute myeloid leukemia and acute myelogenous leukemia are the same disease.

myelogram 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 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.

myeloma Cancer that arises in plasma cells, a type of white blood cell.

myelomatosis A type of cancer that begins in plasma cells (white blood cells that produce antibodies). Also called multiple myeloma, Kahler’s disease or plasma cell myeloma.

myelomonocyte An abnormal type of white blood cell that is found in chronic myelomonocytic leukemia. These cells are similar to both monocytes and myelocytes (immature cells that develop into different types of immune system cells).

myeloproliferative disorder A group of slow growing blood cancers, including chronic myelogenous leukemia, in which large numbers of abnormal red blood cells, white blood cells or platelets grow and spread in the bone marrow and the peripheral blood.

myelosclerosis with myeloid metaplasia A progressive, chronic disease in which the bone marrow is replaced by fibrous tissue and blood is made in organs such as the liver and the spleen, instead of in the bone marrow. This disease is marked by an enlarged spleen and progressive anemia. Also called chronic idiopathic myelofibrosis, agnogenic myeloid metaplasia, primary myelofibrosis and idiopathic myelofibrosis.

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.

myelosuppressive therapy Treatment that inhibits blood cell production.

Mylosar A drug that is used to treat myelodysplastic syndromes and is being studied in the treatment of other types of cancer. It belongs to the family of drugs called antimetabolites. Also called azacitidine and Vidaza.

Mylotarg A monoclonal antibody combined with a toxic substance that is used treat certain types of acute myeloid leukemia in older patients and is being studied in the treatment of other types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to cancer cells. Mylotarg is a type of antibody-drug conjugate. Also called gemtuzumab and gemtuzumab ozogamicin.

myometrium The muscular outer layer of the uterus

Banner MD Anderson Cancer Center
Higley Road and US 60
2946 E. Banner Gateway Drive
Gilbert, AZ 85234
(480) 256-6444
(855) 256-6444

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