A - C D - F G - I L - P R - T U - X
Adenocarcinoma: Cancer that begins in cells that line certain internal organs and that have gland-like properties.
Adrenal gland: A small gland that makes steroid hormones, adrenaline, and noradrenaline. These hormones help control heart rate, blood pressure, and other important body functions. There are two adrenal glands, one on top of each kidney.
Androgen: A type of hormone that promotes the development and maintenance of male sex characteristics.
Anemia: A condition in which the number of red blood cells is below normal.
Antibody: A type of protein made by plasma cells (a type of white blood cell) in response to an antigen (foreign substance). Each antibody can bind to only one 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.
Arsenic: A poisonous chemical used to kill weeds and pests. Also used in cancer therapy.
Barrett esophagus: A condition in which the cells lining the lower part of the esophagus have changed or been replaced with abnormal cells that could lead to cancer of the esophagus. The backing up of stomach contents (reflux) may irritate the esophagus and, over time, cause Barrett esophagus.
Benign: Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body. Also called nonmalignant.
Bone marrow: The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells and platelets.
BRCA1: A gene on chromosome 17 that normally helps to suppress cell growth. A person who inherits certain mutations (changes) in a BRCA1 gene has a higher risk of getting breast, ovarian, prostate, and other types of cancer.
BRCA2: A gene on chromosome 13 that normally helps to suppress cell growth. A person who inherits certain mutations (changes) in a BRCA2 gene has a higher risk of getting breast, ovarian, prostate, and other types of cancer.
Bronchi: The large air passages that lead from the trachea (windpipe) to the lungs.
Calcitonin: A hormone formed by the C cells of the thyroid gland. It helps maintain a healthy level of calcium in the blood. When the calcium level is too high, calcitonin lowers it.
Carcinogen: Any substance that causes cancer.
Catheter: A flexible tube used to deliver fluids into or withdraw fluids from the body.
Cerebellum: 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.
Colon: The longest part of the large intestine, which is a tube-like organ connected to the small intestine at one end and the anus at the other. The colon removes water and some nutrients and electrolytes from partially digested food. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus.
Colonoscope: A thin, tube-like instrument used to examine the inside of the colon. A colonoscope has a light and a lens for viewing and may have a tool to remove tissue.
Dysplastic nevus: A type of nevus (mole) that looks different from a common mole. A dysplastic nevus is often larger with borders that are not easy to see. Its color is usually uneven and can range from pink to dark brown. Parts of the mole may be raised above the skin surface. A dysplastic nevus may develop into malignant melanoma (a type of skin cancer).
Endocrine pancreas cells: A pancreatic cell that produces hormones (e.g., insulin and glucagon) that are secreted into the bloodstream. These hormones help control the level of glucose (sugar) in the blood.
Endometrial hyperplasia: An abnormal overgrowth of the endometrium (the layer of cells that lines the uterus). There are four types of endometrial hyperplasia: simple endometrial hyperplasia, complex endometrial hyperplasia, simple endometrial hyperplasia with atypia, and complex endometrial hyperplasia with atypia. These differ in terms of how abnormal the cells are and how likely it is that the condition will become cancer.
Endometriosis: A benign condition in which tissue that looks like endometrial tissue grows in abnormal places in the abdomen.
Enzymes: Proteins that speed up chemical reactions in the body.
Epidermis: The outer layer of the two main layers of the skin.
Epithelial carcinoma: Cancer that begins in the cells that line an organ.
Epstein-Barr virus: A common virus that remains dormant in most people. It causes infectious mononucleosis and has been associated with certain cancers, including Burkitt lymphoma, immunoblastic lymphoma, and nasopharyngeal carcinoma. Also called EBV.
Exocrine pancreas cells: A pancreatic cell that produces enzymes that are secreted into the small intestine. These enzymes help digest food as it passes through the gastrointestinal tract.
Familial adenomatous polyposis (FAP): An inherited condition in which numerous polyps (growths that protrude from mucous membranes) form on the inside walls of the colon and rectum. It increases the risk of colorectal cancer. Also called familial polyposis and FAP.
Fibroid: A benign smooth-muscle tumor, usually in the uterus or gastrointestinal tract.
Gardner syndrome: An inherited condition in which polyps develop at a young age and often lead to cancer. It can also cause benign tumors of the skin, soft connective tissue, and bones.
Germ cells: A reproductive cell of the body. Germ cells are egg cells in females and sperm cells in males.
Glial cells: Any of the cells that hold nerve cells in place and help them work the way they should. The types of glial cells include oligodendrocytes, astrocytes, microglia and ependymal cells.
Gorlin syndrome: A genetic condition that causes unusual facial features and disorders of the skin, bones, nervous system, eyes and endocrine glands. People with this syndrome have a higher risk of basal cell carcinoma.
Herbicide: A chemical that kills plants.
Hereditary nonpolyposis colon cancer (HNPCC): An inherited disorder in which affected individuals have a higher-than-normal chance of developing colorectal cancer and certain other types of cancer, often before the age of 50. Also called HNPCC and Lynch syndrome.
HIV: The cause of acquired immunodeficiency syndrome (AIDS). Also called human immunodeficiency virus.
Hormone: One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.
Hormone Replacement Therapy (HRT): 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 menopausal hormone therapy.
HTLV-I: A type of virus that infects T cells (a type of white blood cell) and can cause leukemia and lymphoma. HTLV-1 is spread by sharing syringes or needles, through blood transfusions or sexual contact, and from mother to child during birth or breast-feeding. Also called human T-cell leukemia virus type 1 and human T-cell lymphotropic virus type 1.
Human papillomavirus (HPV): A member of a family of viruses that can cause abnormal tissue growth (for example, genital warts) and other changes to cells. Infection with certain types of HPV increases the risk of developing cervical cancer. Also called human papillomavirus.
Indolent lymphoma: A type of lymphoma that tends to grow and spread slowly, and has few symptoms. Also called low-grade lymphoma.
Invasive cancer: Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding healthy tissues. Also called infiltrating cancer.
In situ: In its original place. For example, in carcinoma in situ, abnormal cells are found only in the place where they first formed. They have not spread.
Insulin: A hormone made by the islet cells of the pancreas. Insulin controls the amount of sugar in the blood by moving it into the cells, where it can be used by the body for energy.
Iodine: An element that is necessary for the body to make thyroid hormone. It is found in shellfish and iodized salt.
Large-cell carcinoma: Lung cancer in which the cells are large and look abnormal when viewed under a microscope.
Lymphatic system: The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.
Lymphocyte: A type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue. The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses. A lymphocyte is a type of white blood cell.
Lymphoid: Referring to lymphocytes, a type of white blood cell. Also refers to tissue in which lymphocytes develop.
Lymph 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 lymph gland.
Malignant: Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.
Melanocytes: Cells in the skin and eyes that produce and contain the pigment called melanin.
Meninges: The three thin layers of tissue that cover and protect the brain and spinal cord.
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 the primary site (place where it started) to other places in the body.
Myelodysplastic syndromes: A group of diseases in which the bone marrow does not make enough healthy blood cells.
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.
Pap test: A procedure in which cells are scraped from the cervix for examination under a microscope. It is used to detect cancer and changes that may lead to cancer. A Pap test can also show conditions, such as infection or inflammation, that are not cancer. Also called Pap smear and Papanicoloau test.
Pesticide: Any substance that is used to kill insects and other pests.
Pigment: A substance that gives color to tissue. Pigments are responsible for the color of skin, eyes and hair.
Plasma cell: A type of immune cell that makes large amounts of a specific antibody. Plasma cells develop from B cells that have been activated. A plasma cell is a type of white blood cell. Also called plasmacyte.
Platelet: A tiny piece of a cell found in the blood that breaks off from a large cell found in the bone marrow. Platelets help wounds heal and prevent bleeding by forming blood clots.
Polyp: A growth that protrudes from a mucous membrane.
Prostatic intraepithelial neoplasia (PIN): Noncancerous growth of the cells lining the internal and external surfaces of the prostate gland. Having high-grade prostatic intraepithelial neoplasia may increase the risk of developing prostate cancer.
Radiofrequency ablation: A procedure that uses radio waves to heat and destroy abnormal cells. The radio waves travel through electrodes (small devices that carry electricity).
Rectum: The last several inches of the large intestine closest to the anus.
Red blood cell: A cell that carries oxygen to all parts of the body.
Reed-Sternberg cell: A type of cell that appears in people with Hodgkin disease. The number of these cells increases as the disease advances.
Schwann cell: A type of glial cell of the peripheral nervous system that helps separate and insulate nerve cells.
Soft palate: The back, muscular (not bony) part of the roof of the mouth.
Squamous cells: Flat cell that looks like a fish scale under a microscope. These cells cover inside and outside surfaces of the body. They are found in the tissues that form the surface of the skin, the lining of the hollow organs of the body (such as the bladder, kidney, and uterus), and the passages of the respiratory and digestive tracts.
Squamous cell carcinoma: Cancer that begins in squamous cells, which are thin, flat cells that look like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Also called epidermoid carcinoma.
Stage: The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.
Stem cells: A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.
Stromal cell: A type of cell that makes up certain types of connective tissue (supporting tissue that surrounds other tissues and organs).
Transitional cells: Cells that vary in shape depending on whether the tissue is being stretched. Transitional cells may be stretched without breaking apart. They line hollow organs such as the bladder.
Tuberculosis (TB): A disease caused by a specific type of bacteria that spreads from one person to another through the air. Tuberculosis can affect many parts of the body, but most often affects the lungs. A person may not have symptoms of tuberculosis for years, but they may appear when the patient becomes ill with a serious condition like diabetes, AIDS or cancer. Tuberculosis can usually be treated and cured with antibiotics.
Tumor debulking: Surgical removal of as much of a tumor as possible. Tumor debulking may increase the chance that chemotherapy or radiation therapy will kill all the tumor cells. It may also be done to relieve symptoms or help the patient live longer. Also called debulking.
Urinary tract: The organs of the body that produce and discharge urine. These include the kidneys, ureters, bladder and urethra.
Uterine sarcoma: A rare type of uterine cancer that forms in muscle or other tissues of the uterus (the small, hollow, pear-shaped organ in a woman's pelvis in which a baby grows). It usually occurs after menopause. The two main types are leiomyosarcoma (cancer that begins in smooth muscle cells) and endometrial stromal sarcoma (cancer that begins in connective tissue cells).
Von Hippel-Lindau (VHL) syndrome: A rare inherited disorder in which blood vessels grow abnormally in the eyes, brain, spinal cord, adrenal glands, or other parts of the body. People with von Hippel-Lindau syndrome have a higher risk of developing some types of cancer. Also called VHL syndrome.
White blood cell: A type of immune cell. Most white blood cells are made in the bone marrow and are found in the blood and lymph tissue. White blood cells help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are white blood cells. Also called leukocyte and WBC.
Xeroderma pigmentosum: A genetic condition marked by an extreme sensitivity to ultraviolet radiation, including sunlight. People with xeroderma pigmentosum are not able to repair skin damage from the sun and other sources of ultraviolet radiation, and have a very high risk of skin cancer.
The information on this page is provided by the National Cancer Institute.
