MLH1 and colonic neoplasm: The high level of hypermethylation of the CW-2 cells, however, does not seem to be attributed to the reported elevated level of hypermethylation of sporadic MSI colon cancer (39) because the cells contain a double mutation of MLH1 (a nonsense mutation fixed in homozygosis by copy neutral LOH) rather than its epigenetic silencing by hypermethylation.