Analysis of mismatch repair gene mutations in Turkish HNPCC patients.

Hereditary non-polyposis colorectal cancer is caused by the inheritance of a mutant allele of a DNA mismatch repair gene. We aimed to investigate types and frequencies of mismatch repair (MMR) gene mutations in Turkish patients with HNPCC and to identify specific biomarkers for early diagnosis of their non-symptomatic kindred’s. The molecular characteristics of 28 Turkish colorectal cancer patients at high-risk for HNPCC were investigated by analysis of microsatellite instability (MSI), immunohistochemistry and methylation-specific PCR in order to select tumors for mutation analysis. The present study adds new information about MMR gene mutation types and their role in Lynch syndrome. This is the first detailed research on Turkish Lynch syndrome families.