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Colorectal Cancer Glossary of Terms

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Jejunum: the second portion of the small intestine extending from the duodenum to the ileum.

Laparoscopy or laparoscopic surgery: a method of surgery that is much less invasive than traditional surgery. Tiny incisions are made to create a passageway for a special instrument called a laparoscope. This thin telescope-like instrument with a miniature video camera and light source is used to transmit images to a video monitor. The surgeon watches the video screen while performing the procedure with small instruments that pass through small tubes placed in the incisions.

Large intestine: the digestive organ made up of the ascending (right) colon, the transverse (across) colon, the descending (left) colon the sigmoid (end) colon and the rectum. The colon receives the liquid contents from the small intestine and absorbs the water and electrolytes from this liquid to form feces, or waste. Feces are then stored in the rectum until elimination from the body through the anus.

Laser surgery: destruction of tissue using a small, powerful, highly focused beam of light.

Laxative: medications that increase the action of the intestines or stimulate the addition of water to the stool to increase its bulk and ease its passage. Laxatives commonly are prescribed to treat constipation.

Local therapy: treatment that is directed at cells in the tumor and the area close to it.

Localized cancer: cancer that hasn't spread to other parts of the body.

Lymph: clear fluid that travels through the lymphatic system and carries cells that help fight infection and disease.

Lymphatic system: circulatory system that includes an extensive network of lymph vessels and lymph nodes. The lymphatic system helps coordinate the immune system's function to protect the body from foreign substances.

MRI: a test that produces images of the body without the use of X-rays. MRI uses a large magnet, radio waves, and a computer to produce these images.

Malignant: cancerous; can spread to other parts of the body.

Mesentery: membranous tissue that carries blood vessels and lymph glands, and attaches various organs to the inner wall of the abdomen.

Metastasize: to spread from one part of the body to another. When cancer cells metastasize and cause secondary tumors, the cells in the secondary tumor are like those in the original cancer.

Microsatellite instability: mistakes in DNA. Microsatellite instability is where the length of small sequences of DNA differs between tumor cells and normal cells; their appearance is a clue to the presence of abnormal DNA repair. The presence of microsatellite instability conveys resistance to fluoropyrimidine chemotherapy (5-FU or capecitabine).

Mismatch repair genes: genes responsible for correcting errors in DNA when cells divide. In hereditary non-polyposis colorectal cancer (HNPCC), recent research has discovered mutations in a variety of genes that are thought to be a part of the DNA mismatch repair system, therefore predisposing families with HNPCC to the development of cancer.

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