Lynch syndrome, an inherited syndrome caused by autosomal dominantly inherited germline mutations in one of the MMR genes (hMLH1, hMSH2, hMSH6, hPMS2, EPCAM), is seen in 3% of all CRC patients, whereas sporadic MSI-H status, most commonly due to inactivation of hMLH1, is seen in about 5–20% of all CRCs [2,3,4,5,6]. This evidence concerns the gene MLH1 and Lynch syndrome.