Incidence and functional consequences of hMLH1 promoter hypermethylation in colorectal carcinoma

摘要: Inactivation of the genes involved in DNA mismatch repair is associated with microsatellite instability (MSI) colorectal cancer. We report that hypermethylation 5′ CpG island hMLH1 found majority sporadic primary cancers MSI, and this methylation was often, but not invariably, loss protein expression. Such also occurred, less common, MSI− tumors, as well MSI+ tumors known mutations a gene (MMR). No hMSH2 found. Hypermethylation cancer cell lines MSI frequently observed, such cases, reversal 5-aza-2′-deoxycytidine only resulted reexpression protein, restoration MMR capacity MMR-deficient lines. Our results suggest often from epigenetic inactivation association methylation.