Microsatellite instability in the management of colorectal cancer. (June 2011)

• Record Type: Journal Article
• Authors: Pino, Maria S; Chung, Daniel C
• Is Part Of: Expert review of gastroenterology & hepatology. Volume 5:Number 3(2011)
• Page Start: 385
• Page End: 399
• Publication Date: 2011-06
• Subjects: colorectal cancer -- Lynch syndrome -- microsatellite instability -- mismatch repair genes -- predictive marker -- prognostic marker; Gastroenterology -- Periodicals; Liver -- Diseases -- Periodicals; 616.3
• DOI: 10.1586/egh.11.25
• Languages: English
• ISSNs: 1747-4124

Abstract

Microsatellite instability (MSI) is a form of genetic instability caused by alterations in the DNA mismatch repair system. Approximately 15% of colorectal cancers display MSI due to a germline mutation in one of the mismatch repair genes ( MLH1, MSH2, MSH6 and PMS2 ) or to epigenetic silencing of MLH1 . Colorectal cancers with MSI have distinctive features, including a tendency to arise in the proximal colon, poor differentiation, lymphocytic infiltration and mucinous or signet-ring histology. Patients with MSI tumors appear to have a better prognosis than those with microsatellite stable tumors, but curiously the responses to 5-fluorouracil-based chemotherapy regimens are poorer with MSI tumors. Preliminary data suggest possible advantages of irinotecan-based regimens, but these findings need validation in well-designed clinical trials.