With the development of research on HER-2-targeted therapy for advanced GC, in January 2021, the Food and Drug Administration (FDA) of the United States approved trastuzumab deruxtecan (T-Dxd) for the treatment of unresectable, locally advanced, or metastatic GC, which previously received a trastuzumab regimen, thus further perfecting the targeted treatment of GC. This evidence concerns the gene ERBB2 and gastric cancer.