MLH1 and hereditary nonpolyposis colon cancer: A germ line mutation in one of these corresponding genes, most often MLH1 or MSH2, is the cause of dMMR in patients with Lynch syndrome, formerly Hereditary Non Polyposis Colorectal Cancer (HNPCC), which comprises 0.8–5% of all CRCs (Mecklin, 1987; Rodriguez-Bigas et al, 1997; Cunningham et al, 2001).