Human mismatch repair genes play an important role in maintaining the integrity and stability of genetic information and avoiding genetic mutation. PMS2 is a mismatch repair protein with a molecular weight of 96 kDa, located on chromosome 7. It mainly corrects single base mismatch and small fragment mismatch in vivo. PMS2 forms heterodimer with MLH1 protein and coordinates the binding of other proteins after being activated by ATP to repair DNA errors during cell division. At present, it is mostly used for Lynch syndrome screening together with MLH1, MSH2 and MSH6.