A gene expression-based study from the Asian Cancer Research Group (ACRG) also classified STADs into two major subtypes, MSI and microsatellite stable (MSS), while MSS STADs were further subdivided into three subtypes, epithelial-to-mesenchymal transition (EMT), TP53 active (TP53+), and TP53 inactive (TP53-) (Cristescu et al., 2015). The gene discussed is TP53; the disease is cancer.