TP53 and cancer: Based on the integrated genetic characteristics of GCs, the Asian Cancer Research Group (ACRG) analyzed gene expression in 300 primary gastric tumors and established four molecular subtypes (Fig. 1): the microsatellite stable (MSS)/epithelial-mesenchymal transition (EMT) subtype, microsatellite instable (MSI) subtype, MSS/tumor protein 53 (TP53)+ subtype, and MSS/TP53− subtype [11–13].