Since the landmark ToGA trial established trastuzumab, the anti-HER2 antibody, as first-line therapy for HER2-positive advanced gastric cancer [2], research has expanded to other targets including human epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF) [3], and Claudin 18.2 [4]. This evidence concerns the gene ERBB2 and gastric cancer.