Abstract 819: DNA methylation genome-wide analysis in remnant gastric cancer

Abstract

Abstract Purpose: Although primary gastric cancers (PGC) and remnant gastric cancers (RGC) both originate from the same gastrointestinal organ, they have very distinct clinicopathological behaviors. Due to the importance of chronic inflammation in the carcinogenesis of gastric malignancies, we hypothesized that DNA promoter hypermethylation would play a critical role in the carcinogenesis of RGC as well as PGC. Methods: We investigated the genome-wide DNA methylation patterns of PGC and RGC tissues from 48 patients from an academic medical center in Japan using the Infinium HumanMethylation450 BeadChip assay. The results were validated by quantitative methylation-specific PCR (qMSP) in separate, independent cohorts. Results: We found that in our training cohort of 48 patients, genes from the gastric cancer tissues identified by the Infinium HumanMethylation 450 Beadchip clustered into high and low methylation groups on multivariate analysis (p=0.004, OR=12.33). PGCs contributed significantly to the high methylation group suggesting that the DNA promoter methylation status in PGC is higher than that in RGC. Supporting this conclusion was the finding that in a separate qMSP analysis in a test cohort, the gene A had significantly higher DNA promoter methylation in cancer tissues in the validation PGC tissues than in RGC. Conclusion: This study demonstrated that DNA promoter methylation status in PGC is higher than in RGC. This result may reflect the effects of Helicobacter pylori on the induction of DNA methylation in the remnant stomach. Citation Format: Tomoaki Ito, Kiichi Sugimoto, Hajime Orita, Masahiro Maeda, Hiroshi Moro, Toshikazu Ushijima, Hitoshi Katai, Ryo Wada, Kazuhiro Sakamoto, Koichi Sato, Malcolm V. Brock. DNA methylation genome-wide analysis in remnant gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 819.