L-3,5,5'-tetraiodothyronine(...TEH-truh-i-oh-doh-THY-roh-neen) A hormone that is made by the thyroid gland and contains iodine.
L-377,202A substance that is being studied in the treatment of cancer.
L-778,123An anticancer drug that belongs to the family of drugs called enzyme inhibitors. It may inhibit the transformation of normal cells into cancer cells.
L-arginine(⦠AR-jih-neen) One of the twenty common amino acids (building blocks of proteins).
L-asparaginase(... as-PA-ruh-jih-nayz) A drug that is used to treat acute lymphoblastic leukemia (ALL) and is being studied in the treatment of some other types of…
L-carnitineA form of carnitine, which is a substance made in the muscles and liver. It can be given as a supplement to prevent and treat carnitine deficiency in…
L-glutamic acid(... gloo-TA-mik A-sid) One of twenty amino acids (molecules that join together to form proteins).
L-norgestrel(... nor-JES-trel) A form of the hormone progesterone that is made in the laboratory and used to prevent pregnancy.
L-threo-dihydrosphingosine(...THREE-oh-dy-HY-drose-FIN-guh-seen) A substance that is being studied in the treatment of cancer.
lab-on-a-chipAn instrument that uses very small amounts of fluid on a microchip to do certain laboratory tests.
labial mucosa(LAY-bee-ul myoo-KOH-suh) The inner lining of the lips.
laboratory studyResearch done in a laboratory. These studies may use test tubes or animals to find out if a drug, procedure, or treatment is likely to be useful.
laboratory testA medical procedure that involves testing a sample of blood, urine, or other substance from the body.
lacrimal glandA gland that secretes tears. The lacrimal glands are found in the upper, outer part of each eye socket.
lactase(LAK-tayz) An enzyme that breaks down lactose, a type of sugar found in milk and milk products.
lactate dehydrogenase(LAK-tayt dee-hy-DRAH-jeh-nayz) One of a group of enzymes found in the blood and other body tissues and involved in energy production in cells.
lactic acid(LAK-tik A-sid) A substance made from sugars in milk, by the action of certain enzymes.
lactic acid dehydrogenase(LAK-tik A-sid dee-hy-DRAH-jeh-nayz) One of a group of enzymes found in the blood and other body tissues, and involved in energy production in cells.
Lactiferous ducts(lack tih' fer us)the part of the breast that carries the milk to the nipple.
Lactiferous sinuses(lack-tih'-fer-us si'-nus-sehz)the part of the breast that collects the milk and holds it until it is released through the nipple.
lactoferrin(LAK-toh-fayr-in) A protein that is found in milk, tears, mucus, bile, and some white blood cells and is being studied in the treatment and prevention of…
lactoseA type of sugar found in milk and milk products.
lactose intoleranceThe inability to digest or absorb lactose, a type of sugar found in milk and other dairy products.
laetrile(LAY-eh-tril) A substance found in the pits of many fruits such as apricots and papayas, and in other foods.
LAK cellA white blood cell that is stimulated in a laboratory to kill tumor cells. Also called lymphokine-activated killer cell.
lamina propriaA type of connective tissue found under the thin layer of tissues covering a mucous membrane.
lamivudineA drug used to treat infection caused by viruses.
lamotrigineA drug that is used to help control some types of seizures. It is being studied in the prevention of peripheral neuropathy caused by some chemotherapy…
Langerhans cell histiocytosis(LANG-er-HANZ sel HIS-tee-oh-sy-TOH-sis) A group of rare disorders in which too many Langerhans cells (a type of white blood cell) grow in certain tissues…
lanolin(LA-noh-lin) An oily substance taken from sheep's wool. Lanolin is used in moisturizing creams and lotions to treat dry, itchy skin.
Lanoxin(luh-NOK-sin) A drug used to treat irregular heartbeat and some types of heart failure. It is also being studied in the treatment of some types of cancer.
laparoscope(LA-puh-ruh-SKOPE) A thin, tube-like instrument used to look at tissues and organs inside the abdomen.
laparoscopic prostatectomy(LA-puh-ruh-SKAH-pik PROS-tuh-TEK-toh-mee) Surgery to remove all or part of the prostate with the aid of a laparoscope.
laparoscopic-assisted colectomy(LA-puh-ruh-SKAH-pik... koh-LEK-toh-mee) Surgery done with the aid of a laparoscope to remove all or part of the colon through several small incisions…
laparoscopy(LA-puh-ROS-koh-pee) A procedure that uses a laparoscope, inserted through the abdominal wall, to examine the inside of the abdomen.
laparotomy(LA-puh-RAH-toh-mee) A surgical incision made in the wall of the abdomen.
lapatinib(luh-PA-tih-nib) A drug used with another anticancer drug to treat breast cancer that is HER2 positive and has advanced or metastasized (spread to other…
lapatinib ditosylate(luh-PA-tih-nib dy-TOH-sih-layt) A drug used with another anticancer drug to treat breast cancer that is HER2 positive and has advanced or metastasized…
lappaA plant whose seeds and root have been used in some cultures to treat certain medical problems. It may have antioxidant effects.
large cell cancerA type of non-small cell lung cancer where the cancer cells are large and abnormal.
large cell carcinoma(...KAR-sih-NOH-muh) Lung cancer in which the cells are large and look abnormal when viewed under a microscope.
large granular lymphocyteA type of white blood cell that contains granules with enzymes that can kill tumor cells or microbial cells. Also called natural killer cell and NK cell.
large intestineThe long, tube-like organ that is connected to the small intestine at one end and the anus at the other.
laryngeal(luh-RIN-jee-ul) Having to do with the larynx.
laryngeal cancer(luh-RIN-jee-ul KAN-ser) Cancer that forms in tissues of the larynx (area of the throat that contains the vocal cords and is used for breathing…
laryngectomee(lair-in-JEK-toe-mee) A person whose larynx (voice box) has been removed.
laryngectomy(LA-rin-JEK-toh-mee) An operation to remove all or part of the larynx (voice box).
laryngoscope(luh-RING-goh-SKOPE) A thin, tube-like instrument used to examine the larynx (voice box).
laryngoscopy(LAIR-in-GOSS-kuh-pee) Examination of the larynx (voice box) with a mirror (indirect laryngoscopy) or with a laryngoscope (direct laryngoscopy).
larynx(LAYR-inks) The area of the throat containing the vocal cords and used for breathing, swallowing, and talking. Also called voice box.
laser(LAY-zer) A device that concentrates light into an intense, narrow beam used to cut or destroy tissue.
laser acupuncture(LAY-zer AK-yoo-PUNK-cher) The use of a low-level laser beam instead of an acupuncture needle to stimulate an acupuncture point.
laser surgeryA surgical procedure that uses the cutting power of a laser beam to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.
laser therapy(LAY-zer THAYR-uh-pee) The use of an intensely powerful beam of light to kill cancer cells.
lassitude(LA-sih-tood) A feeling of tiredness, weakness, and lack of interest in daily activities.
late effectsSide effects of cancer treatment that appear months or years after treatment has ended.
late-stage cancerA term used to describe cancer that is far along in its growth, and has spread to the lymph nodes or other places in the body.
latentDescribes a condition that is present but not active or causing symptoms.
lavender(LA-vun-der) A plant with aromatic leaves and flowers that is a member of the mint family.
laxativeA substance that promotes bowel movements.
LCHA group of rare disorders in which too many Langerhans cells (a type of white blood cell) grow in certain tissues and organs including the bones, skin…
LCISA condition in which abnormal cells are found in the lobules of the breast. LCIS seldom becomes invasive cancer; however, having it in one breast…
LDHOne of a group of enzymes found in the blood and other body tissues, and involved in energy production in cells.
lectinA 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.
LED therapy(...THAYR-uh-pee) Treatment with drugs that become active and may kill cancer cells when exposed to light.
LEEPA technique that uses electric current passed through a thin wire loop to remove abnormal tissue.
leflunomideAn anticancer drug that works by inhibiting a cancer cell growth factor. Also called SU101.
legal aid organizationA group or agency that gives legal help to people with low incomes. Health legal aid workers help people with issues related to getting good healthcare…
leiomyoma(LY-oh-my-OH-muh) A benign smooth muscle tumor, usually in the uterus or gastrointestinal tract. Also called fibroid.
leiomyosarcoma(LY-oh-MY-oh-sar-KOH-muh) A malignant (cancerous) tumor of smooth muscle cells that can arise almost anywhere in the body, but is most common in the…
lemonA small, yellow citrus fruit that is a source of citric acid and ascorbic acid (vitamin C).
lenalidomide(leh-nah-LID-oh-mide) A drug that is similar to thalidomide, and is used to treat multiple myeloma and certain types of anemia.
lens (lenz)A clear disk that focuses light, as in a camera or microscope. In the eye, the lens is a clear, curved structure at the front of the eye behind the pupil.
lentinanA beta-glucan (a type of polysaccharide) from the mushroom Lentinus edodes (shiitake mushroom). It has been studied in Japan as a treatment for cancer.
LEP-ETUA form of the anticancer drug paclitaxel that is contained in very tiny, fat-like particles.
lepirudinA drug that inhibits blood clotting. It is being studied in cancer treatment.
leptomeningeal(LEP-toh-meh-NIN-jee-ul) Having to do with the two innermost meninges (thin layers of tissue that cover and protect the brain and spinal cord).
leptomeningeal cancer(LEP-toh-meh-NIN-jee-ul KAN-ser) A tumor that involves the two innermost meninges (thin layers of tissue that cover and protect the brain and spinal cord).
leptomeningeal metastasis(LEP-toh-meh-NIN-jee-ul meh-TAS-tuh-sis) Cancer that has spread from the original (primary) tumor to the two innermost meninges (thin layers of tissue…
leridistimA substance being studied for its ability to stimulate the production of blood cells during chemotherapy. It is a type of colony-stimulating factor.
lerisetron(leh-RIH-seh-tron) A substance being studied in the treatment of nausea and vomiting caused by cancer treatment.
lesion(LEE-zhun) An area of abnormal tissue. A lesion may be benign (noncancerous) or malignant (cancerous).
lestaurtinib(leh-STOR-tih-nib) A drug being studied in the treatment of acute leukemias and some other types of cancer.
Lethargy(LEH-thur-jee) A condition marked by drowsiness and an unusual lack of energy and mental alertness.
letrozole(LET-ruh-zole) A drug used to treat advanced breast cancer in postmenopausal women. Letrozole causes a decrease in the amount of estrogen made by the body.
leucovorin(LOO-koh-VOR-in) The active ingredient in a drug used to reduce the toxic effects of folic acid antagonists (substances that block the action of folic…
leucovorin calcium(LOO-koh-VOR-in KAL-see-um) A drug used to reduce the toxic effects of folic acid antagonists (substances that block the action of folic acid), especially…
leukapheresis(LOO-kuh-feh-REE-sis) Removal of the blood to collect specific blood cells. The remaining blood is returned to the body.
leukemia(loo-KEE-mee-uh) Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the…
Leukocyte(LOO-koh-site) A white blood cell. Refers to a blood cell that does not contain hemoglobin.
Leukopenia(LOO-koh-PEE-nee-uh) A condition in which the number of leukocytes (white blood cells) in the blood is reduced.
leukoplakia(LOO-koh-PLAY-kee-uh) An abnormal patch of white tissue that forms on mucous membranes in the mouth and other areas of the body. It may become cancerous.
leuprolide(LOO-pro-lide) The active ingredient in a drug used to treat symptoms of advanced prostate cancer.
leuprolide acetate(LOO-proh-lide A-seh-tayt) A drug used to treat symptoms of advanced prostate cancer.
leuvectinAn agent that delivers the gene for interleukin-2 (IL-2) into cells to increase production of IL-2 by the cells.
levamisoleAn antiparasitic drug that is also being studied in cancer therapy with fluorouracil.
levels of evidence(LEH-vulz uv EH-vih-dents) A ranking system used to describe the strength of the results measured in a clinical trial or research study.
levetiracetam(lee-vih-ty-RAS-ih-tam) A drug used to treat seizures (involuntary muscle movements) caused by epilepsy (a group of brain disorders).
levocarnitineA form of carnitine, which is a substance made in the muscles and liver. It can be given as a supplement to prevent and treat carnitine deficiency in…