MLH1 and Lynch syndrome: Lynch Syndrome, which accounts for ~2–4% of all CRCs [23], is caused by inactivating germline mutations that typically occur in one of four DNA mismatch repair (MMR) genes (MutL Homolog 1 [MLH1], MutS Homolog 2 [MSH2], MutS Homolog 6 [MSH6] and Postmeiotic Segregation Increased 2 [PMS2]), or much rarer, Epithelial Cell Adhesion Molecule [EPCAM] alterations that adversely impact the MSH2 promoter, preventing its expression [22,26].