The prevalence of gastric cancer (GC) differs among regions worldwide, with the highest occurrence in east Asia. Thus, its etiology, with respect to ethnic background, environmental factors, and lifestyles, is also thought to differ essentially. In addition, etiology of GC is speculated to be changing due to the recent decrease in the Helicobacter pylori (H. pylori) infection in Japan. State-of-the-art somatic/germline cancer genomics has clarified the etiologies of gastric carcinogenesis. In this review article, we summarize past and present milestones in our understanding of GC achieved through genomic approaches, including a recent report that revealed higher-than-expected frequencies of GCs attributed to east Asian-specific germline variants in ALDH2 or CDH1 in combination with lifestyles. Based on this updated knowledge, we also discuss the possible impact of and high-risk approaches for GCs in the upcoming “H. pylori-negative era.”

胃癌（GC）的患病率在世界各地不同，东亚的发生率最高。因此，在种族背景、环境因素和生活方式方面，其病因也被认为存在本质差异。此外，由于最近日本幽门螺杆菌( H. pylori ) 感染的减少，推测 GC 的病因正在发生变化。最先进的体细胞/生殖系癌症基因组学已经阐明了胃癌发生的病因。在这篇综述文章中，我们总结了我们通过基因组方法实现的对 GC 理解的过去和现在的里程碑，包括最近的一份报告，该报告揭示了归因于东亚特异性生殖系变异的ALDH2或CDH1与生活方式相结合。基于这些更新的知识，我们还讨论了在即将到来的“幽门螺杆菌阴性时代”中GC 的可能影响和高风险方法。