Although the majority of late-onset CRC is located in the distal colon and microsatellite stable (MSS), some features more characteristic of late-onset CRC include occurrence in the proximal colon, as well as the presence of MSI via MLH1 gene promoter methylation, chromosomal instability, and a high CpG island methylator phenotype, especially when compared with sporadic early-onset CRC11. This evidence concerns the gene MLH1 and colorectal carcinoma.