Is Associated with Expression through Promoter Methylation in Gastric Carcinogenesis.

Background/aims: To investigate whether eradication can reverse epigenetic silencing of microRNAs (miRNAs) which are associated with -induced gastric carcinogenesis.

Methods: We examined expression and promoter methylation of , , , and in gastric cancer cell line, before/after demethylation. Among them, epigenetically controlled miRNAs were identified. Their expression and promoter methylation was examined in human tissues of -positive gastric cancer (T), -positive gastritis (H), and -negative controls (C). We also compared changes of miRNA expression and promoter methylation in -positive patients who were endoscopically treated for early gastric cancer, between baseline and 1 year later according to eradication status.

Results: In gastric cancer cell line, and showed epigenetic silencing. In human tissues, and showed serial increase of promoter methylation in order of C, H, and T (all, p＜0.01), and the expression showed serial decrease (C vs H, p=0.02; H vs T, p=0.01; C vs T, p＜0.01) while and expressions did not. eradication induced decrease of methylation (p＜0.01) and increase of expression (p=0.03), compared with noneradication group.

Conclusions: This result suggests eradication could reverse methylation-silencing of which is involved in -induced gastric carcinogenesis.