A multivariate Cox regression analysis including GSK3B, CTNNB1, DNMT1 and the standard prognostic variables in GC, namely ypT, ypN, ypM and resection category revealed GSK3B as the second most important independent prognostic factor (HR: 0.128, 95% CI: 0.033–0.492, p = 0.003) after distant metastasis (Table S1). This evidence concerns the gene DNMT1 and gastric cancer.