Postmeiotic Segregation Increased 2 (PMS2) is a DNA repair protein involved in mismatch repair. Mutations and deficiencies in the PMS2 gene have been linked to microsatellite instability, and malignancies such as hereditary nonpolyposis colorectal cancer and endometrial cancer. Expression levels of the PMS2 protein may be useful as a screening tool for Lynch syndrome after a colorectal cancer diagnosis. Anti-PMS2 is recommended to be used as part of a panel along with antibodies against MLH1, MSH2, and MSH6.