L-377,202: A substance that is being studied in the treatment of cancer.

L-778,123: An anticancer drug that belongs to the family of drugs called enzyme inhibitors. It may inhibit the transformation of normal cells into cancer cells.

Lactose intolerance: The inability to digest or absorb lactose, a type of sugar found in milk and other dairy products.

Lamivudine: A drug used to treat infection caused by viruses.

Laparoscopic-assisted colectomy: Surgery done with the aid of a laparoscope (a thin, lighted tube) to remove part or all of the colon through small incisions made in the wall of the abdomen.

Laparoscopy (lap-a-RAHS-ko-pee): The insertion of a thin, lighted tube (called a laparoscope) through the abdominal the abdominal wall to inspect the inside of the abdomen and remove tissue samples.

Laparotomy (lap-a-RAH-toe-mee): A surgical incision made in the wall of the abdomen.

Large cell carcinomas (kar-sin-O-mas): A group of lung cancers in which the cells are large and look abnormal when viewed under a microscope.

Laryngeal (lair-IN-jee-al): Of, relating to, affecting, or near the larynx.

Laryngectomee (lair-in-JEK-toe-mee): A person whose larynx (voice box) has been removed.

Laryngectomy (ctomy (lair-in-JEK-toe-mee): An operation to remove all or part of the larynx (voice box).

Laryngoscope (lair-IN-jo-skope): A thin, lighted tube used to examine the larynx (voice box).

Laryngoscopy (lair-in-GOS-ko-pee): Examination of the of the larynx (voice box) with a mirror (indirect laryngoscopy) or with a laryngoscope (direct laryngoscopy).

Larynx (LAIR-inarynx (LAIR-inks): The area of the throat containing the vocal cords and used for breathing, swallowing, and talking. Also called the voice box.

Laser (LAY-zer): A device that concentrates light into an intense, narrow beam used to cut or destroy tissue. It is used in microsurgery, photodynamic therapy, and for a variety of diagnostic purposes.

Laser therapy: The use of an intensely powerful beam of light to kill cancer cells.

Lectin: 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.

Leflunomide: An anticancer drug that works by inhibiting a cancer cell growth factor. Also called SU101.

Leiomyoma: A benign smooth-muscle tumor, usually in the uterus or gastrointestinal tract. Also called fibroid.

Leiomyosarcoma: A tumor of the muscles in the uterus, abdomen, or pelvis.

Lentinan: A beta-glucan (a type of polysaccharide) from the mushroom Lentinus edodes (shiitake mushroom). It has been studied in Japan as a treatment for cancer.

Lepirudin: A drug that inhibits blood clotting; it is being studied in cancer treatment.

Leptomeningeal cancer: A tumor that involves the tissues that cover the brain and spinal cord.

Leptomeningeal metastases: Cancer that has spread from the original (primary) tumor to the tissues that cover the brain and spinal cord.

Lerid cord: Cancer that has spread from the original (primary) tumor to the tissues that cover the brain and spinal cord.

Lerisetron: A drug that prevents or reduces nausea and vomiting.

Lesion (LEE-zhun): An area of abnormal tissue change.