ERBB2 and gastric cancer: Targeted therapies approved for the treatment of GC include epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2) (Trastuzumab), vascular endothelial growth factor (VEGF) (Ramosumab), mammalian target of rapamycin (mTOR) and Claudin 18.2 (CLDN 18.2) [7–9].