Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry-based Detection of Microsatellite Instabilities in Coding DNA Sequences: A Novel Approach to Identify DNA-Mismatch Repair-deficient Cancer Cells

Abstract
Background: Inherited defects in the DNA mismatch repair system lead to increased loss or gain of repeat units in microsatellites, commonly referred to as microsatellite instability (MSI). MSIs in coding regions of critical genes contribute to the pathogenesis of DNA-mismatch repair-deficient cancers, particularly those associated with the hereditary nonpolyposis colorectal cancer syndrome (HNPCC). MSI typing is therefore increasingly used to guide the molecular diagnosis of HNPCC.