Owing to increasing insights into the molecular characteristics of gastric cancer since 2012 [2,3], various molecular-targeted agents and immune therapeutics, including ramucirumab (anti-vascular endothelial growth factor receptor 2), trastuzumab (anti-human epidermal growth factor receptor 2), nivolumab (anti-programmed death receptor 1 (PD-1)), and pembrolizumab (anti-PD-1), are currently approved and are part of gastric cancer treatment protocols. This evidence concerns the gene ERBB2 and gastric cancer.