Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is an autosomal dominantly inherited condition caused by germline mutations in one of the mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2. It is estimated that about 2%-5% of all diagnosed colorectal and endometrial cancers are due to Lynch syndrome [1]. Here, MLH1 is linked to Lynch syndrome.