PIK3CA and neoplasm: Activation of the PI3K‐AKT‐mTOR pathway in tumours is due to point mutations or amplifications of kinases (PIK3CA, AKT and MTOR), upstream receptor tyrosine kinases (epidermal growth factor receptor [EGFR], HER2, MET and FGFR) or small GTPases of the RAS family (HRAS, KRAS and NRAS).