The genetics of hereditary non-polyposis colorectal cancer

Abstract

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant condition accounting for 3% to 5% of all colorectal cancer. HNPCC is caused by germline mutations in the mismatch repair system and is recognized by a characteristic clinical phenotype as well as a hallmark of the tumors termed "microsatellite instability." Microsatellite instability serves as a molecular fingerprint for defective mismatch repair and has proven to be useful in the molecular diagnostic workup for HNPCC. The crystal structure of the DNA mismatch repair protein MutS has been solved, providing insight into the molecular basis of defective mismatch repair. Genetic testing has become a key component of the treatment of patients and families with HNPCC, and enhanced surveillance for HNPCC has been shown to reduce the rate of colorectal cancer by more than half and improve 10-year survival from 68% to 93%. © Journal of the National Comprehensive Cancer Network. All rights reserved.