MLH1 and colorectal carcinoma: Regarding genetic factors, DNA mismatch repair genes, such as MutL homolog 1 (MLH1), MutS homolog 2 (MSH2), MutS homolog 6 (MSH6), and PMS1 homolog 2 (PMS2), and inherited germ-line mutations of the adenomatous polyposis coli (APC) gene play a key role in predisposing individuals to CRC (5, 6).