ERBB2 and gastric cancer: Numerous genomic alterations can be found in gastric cancer, including mechanistic target of rapamycin, human epidermal growth factor receptor 2 (HER2), tyrosine-protein kinase Met (MET), epidermal growth factor receptor, fibroblast growth factor receptor-2, phosphoinositide 3-kinase, microsatellite instability, and claudin 18.2.