Mismatch repair endonuclease PMS2 is an enzyme that is involved in DNA mismatch repair. This gene is deficient in many patients with microsatellite instability and it is commonly associated with Hereditary Non-Polyposis Colon Cancer (HNPCC). This antibody is useful in screening patients and families for this condition and is utilized in an IHC panel that includes the antibodies MLH1, MSH2 and MSH6.