MLH1 and colorectal carcinoma: About 15% of CRC exhibit dMMR5 with 2–3% caused by germline mutations in the MLH1, MSH2, MSH6, PMS2 or EPCAM genes6 while 12% of CRC cases have somatic inactivation of MLH1 via promoter hypermethylation (MLH1-hm)7.