Microsatellite instability markers for identifying early-onset colorectal cancers caused by germ-line mutations in DNA mismatch repair genes

Abstract

Purpose: Microsatellite instability (MSI) testing of colorectal cancer tumors is used as a screening tool to identify patients most likely to be mismatch repair (MMR) gene mutation carriers. We wanted to examine which microsatellite markers currently used to detect MSI best predict early-onset colorectal cancer caused by germ-line mutations in MMR genes. Experimental Design: Invasive primary tumors from a population-based sample of 107 cases of colorectal cancer diagnosed before age 45 years and tested for germ-line mutations in MLHI, MSH2, MSH6, and PMS2 and MMR protein expression were screened for MSI using the National Cancer Institute panel and an expanded 10-microsatellite marker panel...