Microsatellite instability in stage II colorectal cancer: An Indian perspective

Abstract

Introduction: Around 80% of colorectal carcinoma are associated with chromosomal instability (CIN) while rest of 20 % are euploid, possessing defect in mis match repair system (MMR) quintessential for surveillance and correction of errors in introduced into microsatellites.

Materials and methods: We analyse all stage II CRC for MSI who presented at MDTC at Army hospital (research and refrral) new delhi during last 2 years (Jan 14 to Dec 2015).

Results: We found that 22.2% patients out of 45 patients with stageII CRC being MSI-. high. We also noticed all suchcases were associated with loss of expression of PMS2 & MLH1, that was in contrast other studies where loss of MLH1 and MSH@, MSH6 were seen more commonly.

Conclusion: MSI occurs in a significant proportion of colorectal cancers in young (<50 years old) patients. Young age at colorectal cancer diagnosis, proximal tumor location, family history of colorectal cancer were independent predictors of MSI status in our patients. In a proportion of these young patients with MSI tumors, loss of expression of proteins by 2 MMR genes PMS2 and hMLH1 has been identified.