Targeted therapy has shown limited efficacy in GC patients, since HER2-targeted Trastuzumab, VEGFA/VEGFR2-targeted Bevacizumab, Ramucirumab, Apatinob, Regorafenib, and some immunomodulators such as Nivolumab for PD-L1 positive metastatic GC, are the only effective therapies so far, and most clinical trials evaluating targeted treatments with approved efficacy in other cancer types have failed in gastric cancer. The gene discussed is ERBB2; the disease is gastric cancer.