Ventana Medical Systems, Inc. PMS2 760-4531

Microsatellite instability (MSI) is characterised by genome-wide alterations in short, repetitive DNA sequences. It is caused by defects in the nucleotide mismatch repair (MMR) system. Biologically, defective MMR results in a general increase in the mutation rate and the development of a “mutator phenotype.” In colorectal cancer (CRC), high-level MSI was first described in tumors from patients with hereditary non-polyposis colorectal cancer (HNPCC). PMS2 is a useful diagnostic and prognostic marker for hereditary non-polyposis colorectal cancer (HNPCC).