MLH1 and hereditary nonpolyposis colon cancer: Lynch syndrome or hereditary non-polyposis colorectal cancer (HNPCC) is characterized by germline inactivation of one allele of genes involved in the mismatch repair system, namely MLH1, MSH2, MSH6, PMS2 or EPCAM and have received prominent clinical and research attention and since 1985 (1, 2).