In the final combined analysis that included the discovery and extension analyses, the risk estimates of ERK rs5999749 were significantly associated with gastric cancer in both the pooled analysis and meta-analysis (OR = 1.57, [95% CI: 1.20–2.07]; OR = 1.56, [95% CI: 1.19–2.06], respectively). Here, MAPK1 is linked to gastric cancer.