AKT1 and neoplasm: The tumour suppressor PTEN dephosphorylates the lipid second messenger phosphoinositol 3,4,5‐trisphosphate (PIP3), an enzymatic product of PI3K, and negatively regulates survival signalling mediated by PI3K/protein kinase B/Akt (PI3K/PKB/Akt) 14, 15.