AKT1 and neoplasm: PTEN is a major tumor suppressor that antagonizes the PI3K/Akt (also known as protein kinase B, PKB) pro-survival and -proliferation signaling pathway by dephosphorylating the lipid second messenger phosphatidylinositol (3, 4, 5)-trisphosphate (PIP3) to phosphatidylinositol (4,5)-bisphosphate (PIP2) [1].