DNA methylation of microRNA genes in gastric mucosae of gastric cancer patients: its possible involvement in the formation of epigenetic field defect.

摘要: Accumulation of aberrant DNA methylation in normal-appearing gastric mucosae, mostly induced by H. pylori infection, is now known to be deeply involved predisposition cancers (epigenetic field defect), and silencing protein-coding genes has been analyzed so far. In this study, we aimed clarify the involvement microRNA (miRNA) gene defect. First, selected three miRNA as methylation-silenced after analysis six candidate "methylation-silenced" tumor-suppressor genes. Methylation levels (miR-124a-1, miR-124a-2 miR-124a-3) were quantified 56 normal mucosae healthy volunteers (28 with 28 without), 45 noncancerous cancer patients (29 16 tissues (13 intestinal 15 diffuse types). Among volunteers, individuals had 7.8-13.1-fold higher than those without (p < 0.001). pylori, 7.2-15.5-fold 0.005). Different from genes, past infection retained similar current infection. tissues, highly variable, no difference was observed between histological types. This strongly indicated that methylation-silencing addition contributed formation a defect for cancers.