MSH6 is a heterodimer of MSH2 and binds to DNA containing G/T mismatches. MLH-1 and MSH2 are involved in the DNA mismatch repair (MMR) process. Microsatellite instability (MSI) is an alteration of microsatellite repeats during DNA replication and is a hallmark of the inactivation of the MMR genes. These defects in MMR have been related to human carcinogenesis. Studies have shown the mutations in MSH-1, MSH2 and MSH6 genes contribute to the development of sporadic colorectal carcinoma. MSH6 antibody may be useful to aid in identifying the most probable gene responsible for the MSI.