The Asian Cancer Research Group (ACRG) newly proposed a classification system where GC is divided into four subtypes: microsatellite instable (MSI) subtype, microsatellite stable/epithelial-to-mesenchymal transition (MSS/EMT) subtype, microsatellite stable/the tumor protein 53 active (MSS/TP53+) subtype, and microsatellite stable/the tumor protein 53 inactive (MSS/TP53-) subtype 5, 6. The gene discussed is TP53; the disease is gastric cancer.