MLH1 and Inherited cancer-predisposing syndrome: Lynch syndrome, a hereditary cancer syndrome, occurs because of germline mutations in at least one of four DNA mismatch repair genes (MutL Homolog 1 (MLH1), MutS Homolog 2 (MSH2), MutS Homolog 6 (MSH6), and PMS1 Homolog 2 (PMS2)).