MSH6 (also known as GTBP) was isolated from HeLa cells by virtue of its ability to restore mismatch repair to nuclear extracts of MSH2-deficient colorectal tumor cell lines. MutS Homolog 6 (MSH6) is part ofDNA repair pathways and play a key role onmutator S protein (hMutSα) shuttling. MSH6 has ATPase activity that is critical in mismatch repair. Germline mutations in MSH6 is associated with hereditary nonpolyposis colon cancer and in endometrial carcinoma.