Abstract
PURPOSE: This study aimed to investigate whether MOS methylation can be useful for the prediction of metachronous recurrence after endoscopic resection of gastric neoplasms. MATERIALS AND METHODS: From 2012 to 2017, 294 patients were prospectively enrolled after endoscopic resection of gastric dysplasia (n=171) or early gastric cancer (n=123). When Helicobacter pylori was positive, eradication therapy was performed. Among them, 124 patients completed the study protocol (follow-up duration > 3 years or development of metachronous recurrence during the follow-up). Methylation levels of MOS were measured at baseline using quantitative MethyLight assay from the antrum. RESULTS: Median follow-up duration was 49.9 months. MOS methylation levels at baseline were not different by age, sex, and current H. pylorii infection, but they showed a weak correlation with operative link on gastritis assessment (OLGA) or operative link on gastric intestinal metaplasia assessment (OLGIM) stages (Spearman's ρ=0.240 and 0.174, respectively; p < 0.05). During the follow-up, a total of 20 metachronous gastric neoplasms (13 adenomas and 7 adenocarcinomas) were developed. Either OLGA or OLGIM stage was not useful in predicting the risk for metachronous recurrence. In contrast, MOS methylation high group (≥ 34.82%) had a significantly increased risk for metachronous recurrence compared to MOS methylation low group (adjusted hazard ratio, 4.76; 95% confidence interval, 1.54 to 14.79; p=0.007). CONCLUSION: MOS methylation can be a promising marker for predicting metachronous recurrence after endoscopic resection of gastric neoplasms. To confirm the usefulness of MOS methylation, validation studies are warranted in the future (ClinicalTrials No. NCT04830618).