ERBB2 and gastric cancer: Since approximately 21% of patients with GC carry HER2-overexpressed tumors (3), and HER2-overexpressed tumors are more aggressive than HER2-wild type tumors (4, 5), HER2-based targeted therapies, such as trastuzumab (brand name Herceptin) and its derivatives, pertuzumab (brand name Perjeta), and zanidatamab (brand name Ziihera), are considered as frontline treatment for those patients with HER2-overexpressed GC (6, 7).