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Hereditary Nonpolyposis Colorectal Cancer Definition
Hereditary Nonpolyposis Colorectal Cancer (HNPCC) – a form of COLORECTAL CANCER predisposed by a mutation in the mlh1 and msh1 genes. These genes direct DNA repair mechanisms, the processes cells follow to correct mistakes that occur when they replicate their DNA codes during cell reproduction, for cells in the mucous membrane lining of the COLON and RECTUM. Having the GENE mutations for HNPCC increases the likelihood that a person will develop colorectal CANCER before the age of 50 years. HNPCC accounts for about 5 percent of colorectal cancer in the United States as well as increased risk for GASTRIC CANCER, ENDOMETRIAL CANCER, and OVARIAN CANCER.
Cancer experts recommend annual COLONOSCOPY (examination of the colon with a flexible, lighted scope) to screen for colorectal cancer when HNPCC mutations are present, beginning at age 20 or upon identification of the mutations. Such screening permits the early detection and removal of the intestinal polyps that are the preliminary foundation for colorectal cancer. Polyps tend to progress to malignancy much faster in people who have genetic predisposition to colorectal cancer. Such aggressive screening has good potential for preventing colorectal cancer. GENETIC TESTING is important as well.
See also ADENOMA-TO-ADENOCARCINOMA TRANSITION; CANCER PREVENTION; CANCER RISK FACTORS; CELL STRUCTURE AND FUNCTION; FAMILIAL ADENOMATOUS POLYPOSIS (FAP); GENETIC DISORDERS; GENETIC TESTING; INHERITANCE PATTERNS; INTESTINAL POLYP.