Following the publication of the practice-changing “phase III ToGA” trial [4], trastuzumab (anti-HER2 drug)-containing regimen was licensed as the standard of care for HER2-p tumor both by the National Comprehensive Cancer Network (NCCN), European Society for Medical Oncology (ESMO), Japanese Gastric Cancer Association (JGCA) and Chinese Society of Clinical Oncology (CSCO) [5–8]. The gene discussed is ERBB2; the disease is gastric cancer.