PIK3CA and neoplasm: Right–sided tumours are characterized by the following features: mucinous and signet ring histology; hypermutable microsatellite instable (MSI)-high and CpG island methylator phenotype (CIMP)-high phenotypes; poorly differentiated; infiltrated with immune cells; and have higher mutation rates of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), Kirsten rat sarcoma virus (KRAS) and B-Raf murine sarcoma viral oncogene homologue B (BRAF).