TP53 and cancer: The Asian Cancer Research Group (ACRG) also provides another classification of the four mentioned GC subtypes, as follows: (i) MSI, (ii) epithelial-to-mesenchymal transition (EMT)/GC, (iii) microsatellite stable with intact TP53 activity (MSS/TP53+), and (iv) microsatellite stable GC with loss of TP53 activity (MSS/TP53−) [33,34].