Cancer Dictionary

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T cell: One type of white blood cell that attacks virus-infected cells, foreign cells and cancer cells. They also produce a number of substances that regulate the immune response.

T-cell depletion: Treatment to destroy T cells, which play an important role in the immune response. Elimination of T cells from a bone marrow graft from a donor may reduce the chance of an immune reaction against the recipient's tissues.

T-cell lymphoma (lim-FO-ma): A disease in which certain cells of the lymph system (called T lymphocytes) become cancerous.

T138067: An anticancer drug that belongs to the family of drugs called mitotic inhibitors. It inhibits the growth of cancer cells by preventing cell division.

T4N5 liposomal lotion: Enzyme lotion used in treating xeroderma pigmentosum.

tacrolimus: A drug used to help reduce the risk of rejection by the body of organ and bone marrow transplants.

TAG-72 antigen: A protein/sugar complex found on the surface of many cancer cells, including breast, colon and pancreatic cells.

tamoxifen: An anticancer drug that belongs to the family of drugs called antiestrogens. Tamoxifen blocks the effects of the hormone estrogen in the body. It is used to prevent or delay the return of breast cancer or to control its spread.

taxanes: Anticancer drugs that inhibit cancer cell growth by stopping cell division. Also called antimitotic or antimicrotubule agents or mitotic inhibitors.

technetium Tc 99m dextran: A radiolabeled substance that is used in cancer diagnosis.

technetium Tc 99m sulfur colloid: A radiolabeled substance that is used to help identify sites of tumor development.

tegafur: An anticancer drug that belongs to the family of drugs called antimetabolites.

temoporfin: An anticancer drug that is also used in cancer prevention. It belongs to the family of drugs called photosensitizing agents.

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

teniposide: An anticancer drug that is a podophyllotoxin derivative and belongs to the family of drugs called mitotic inhibitors.

terminal disease: Disease that cannot be cured and will cause death.

testicles (TES-tih-kuls): The two egg-shaped glands found inside the scrotum. They produce sperm and male hormones. Also called testes.

testosterone (tes-TOS-ter-own): A hormone that promotes the development and maintenance of male sex characteristics.

tetracycline: An antibiotic drug used to treat infection.

TG4010: A substance that is being studied as an anticancer drug.

thalidomide: A drug that belongs to the family of drugs called angiogenesis inhibitors. It prevents the growth of new blood vessels into a solid tumor.

theophylline: A drug used to improve breathing in people who are short of breath. It belongs to the family of drugs called bronchodilators or respiratory smooth muscle relaxants.

therapeutic: Used to treat disease and help healing take place.

thioguanine: An anticancer drug that belongs to the family of drugs called antimetabolites.

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

thoracentesis (thor-a-sen-TEE-sis): Removal of fluid from the pleural cavity through a needle inserted between the ribs.

thoracic (thor-ASS-ik): Having to do with the chest.

thoracoscopy: The use of a thin, lighted tube (called an endoscope) to examine the inside of the chest.

thoracotomy (thor-a-KAH-toe-mee): An operation to open the chest.

thrombocytes (THROM-bo-sites): Blood cells that help prevent bleeding by causing blood clots to form. Also called platelets.

thrombocytopenia: 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.

thrombophlebitis (throm-bo-fleh-BY-tis): Inflammation of a vein that occurs when a blood clot forms.

thrombopoietin: A colony-stimulating factor that stimulates the production of blood cells, especially platelets, during chemotherapy. It is a cytokine that belongs to the family of drugs called hematopoietic (blood forming) agents.

thymidine: A chemical compound found in DNA. Also used as treatment for mucositis.

thymoma: A tumor of the thymus, an organ that is part of the lymphatic system and is located in the chest, behind the breastbone.

thymus: An organ that is part of the lymphatic system, in which T lymphocytes grow and multiply. The thymus is in the chest behind the breastbone.

thyroid: A gland located near the windpipe (trachea) that produces thyroid hormone, which helps regulate growth and metabolism.

tiazofurin: An anticancer drug being studied to stop cell growth.

tin ethyl etiopurpurin: An anticancer drug that is also used in cancer prevention. It belongs to the family of drugs called photosensitizing agents. Also called SnET2.

tin Sn 117m DTPA: A radioactive chemical being studied to treat bone pain associated with cancer.

tinidazole: A drug used to treat protozoal infections, such as amebiasis, giardiasis and trichomoniasis. It belongs to a family of drugs called antiprotozoal agents. Tinidazole is also being evaluated in the treatment of H. pylori infections in people with low-grade gastric lymphoma.

tirapazamine: A drug that makes tumor cells more sensitive to radiation therapy.

tissue (TISH-oo): A group or layer of cells that are alike in type and work together to perform a specific function.

TNP-470: A drug that belongs to the family of drugs called angiogenesis inhibitors. It prevents the growth of new blood vessels into a solid tumor.

tonsils: Small masses of lymphoid tissue on either side of the throat.

topical: On the surface of the body.

topical chemotherapy (kee-mo-THER-a-pee): Treatment with anticancer drugs in a lotion or cream applied to the skin.

topoisomerase inhibitors: A family of anticancer drugs. The topoisomerase enzymes are responsible for the arrangement and rearrangement of DNA in the cell and for cell growth and replication. Inhibiting these enzymes may kill cancer cells or stop their growth.

topotecan: An anticancer drug that belongs to the family drugs called topoisomerase inhibitors.

toremifene: An anticancer drug that belongs to the family of drugs called antiestrogens. Toremifene blocks the effect of the hormone estrogen in the body. It may help control some cancers from growing and it may delay or reduce the risk of cancer recurrence.

total androgen blockade: Therapy used to eliminate male sex hormones (androgens) in the body. This may be done with surgery, hormonal therapy, or a combination.

total estrogen blockade: Therapy used to eliminate estrogen in the body. This may be done with surgery, radiation therapy, chemotherapy, or a combination of these procedures.

total hysterectomy: Surgery to remove the entire uterus.

total mastectomy (mas-TEK-toe-mee): Removal of the breast. Also called simple mastectomy.

total nodal irradiation: Radiation therapy to the mantle field, the spleen, the lymph nodes in the upper abdomen and the lymph nodes in the pelvic area.

total pancreatectomy: Surgery to remove the entire pancreas.

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.

toxins: Poisons produced by certain animals, plants, or bacteria.

TPA: 12-O-tetradecanoylphorbol-13-acetate. A drug that is being studied as a treatment for hematologic cancer.

tracer: A substance (such as a radioisotope) used in imaging procedures.

trachea (TRAY-kee-a): The airway that leads from the larynx to the lungs. Also called the windpipe.

tracheoesophageal puncture (TRAY-kee-o-eh-SOF-a-JEE-al PUNK-chur): A small opening made by a surgeon between the esophagus and the trachea. A valve keeps food out of the trachea but lets air into the esophagus for esophageal speech.

tracheostomy (TRAY-kee-AHS-toe- mee): Surgery to create an opening (stoma) into the windpipe. The opening itself may also be called a tracheostomy.

tracheostomy button (TRAY-kee-AHS-toe-mee): A 0.5-inch- to 1.5-inch-long plastic tube placed in a surgically created opening (tracheostomy) in the windpipe to keep it open.

tracheostomy tube (TRAY-kee-AHS-toe-mee): A 2-inch- to 3-inch-long curved metal or plastic tube placed in a surgically created opening (tracheostomy) in the windpipe to keep it open. Also called a trach ("trake") tube.

Transcendental Meditation: A mental technique used to promote relaxation, reduce stress and improve quality of life.

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.

transitional cell carcinoma: A type of cancer that develops in the lining of the bladder, ureter, or renal pelvis.

transitional cells: Cells lining some organs.

transplantation: The replacement of an organ with one from another person.

transrectal ultrasound: A procedure used to examine the prostate. An instrument is inserted into the rectum and sound waves bounce off the prostate. These sound waves create echoes, which a computer uses to create a picture called a sonogram.

transurethral resection: Surgery performed with a special instrument inserted through the urethra. Also called TUR.

transurethral resection of the prostate (TRANZ-yoo-REE-thral ree-SEK-shun): Surgical procedure to remove tissue from the prostate using an instrument inserted through the urethra. Also called TURP.

transvaginal ultrasound: A procedure used to examine the vagina, uterus, fallopian tubes and bladder. An instrument is inserted into the vagina and sound waves bounce off organs inside the pelvic area. These sound waves create echoes, which a computer uses to create a picture called a sonogram. Also called TVS.

trastuzumab: 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. Trastuzumab blocks the effects of the growth factor protein HER2, which transmits growth signals to breast cancer cells.

tretinoin: A drug that belongs to the family of drugs called retinoids. It is used in the treatment of acne and is being studied in cancer prevention.

triacetyluridine: A substance that is being studied for its ability to protect against the gastrointestinal side effects caused by fluorouracil. It is a precursor of uridine, which is a component of RNA.

tributyrin: A triglyceride drug that may inhibit cell growth and induce cell differentiation. Differentiating agents may be effective in changing cancer cells back into normal cells.

trichothiodystrophy: A hereditary condition characterized by sparse and brittle hair, short stature and mental retardation.

trimethoprim-sulfamethoxazole: An antibiotic drug used to treat infection and prevent pneumocystis carinii pneumonia.

trimetrexate glucuronate: A drug that belongs to the family of drugs called antimetabolites. It is used in the treatment of pneumocystis carinii pneumonia and is being studied in the treatment of cancer.

triptorelin: A hormonal anticancer drug that belongs to the family of drugs called gonadotropin-releasing hormones.

troglitazone: A drug used in diabetes treatment that is being studied for its effect on reducing the risk of cancer cell growth in fat tissue.

troxacitabine: A drug being studied for use as an anticancer agent.

tubal ligation (TOO-bul lye-GAY-shun): An operation to tie the fallopian tubes closed. This procedure prevents pregnancy by blocking the passage of eggs from the ovaries to the uterus.

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

tumor antigen vaccine: A vaccine made of tumor antigens (proteins isolated from tumor cells).

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

tumor infiltrating lymphocytes: White blood cells that have left the bloodstream and migrated into a tumor.

tumor marker: A substance sometimes found in an increased amount in the blood, other body fluids, or tissues and which 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).

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

tumor-derived: Taken from an individual's own tumor tissue; may be used in the development of a vaccine that enhances the body's ability to build an immune response to the tumor.

tyrosinase peptide: A tumor-specific antigen used in the development of cancer vaccines.

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This cancer dictionary is provided by the National Cancer Institute.