PTEN is a haploinsufficient tumour suppressor that inhibits growth signaling by dephosphorylating phosphatidylinositol 3,4,5-trisphosphate (PIP3), the product phosphatidylinositol 3-kinase (PI3K) that in turn activates AKT (Georgescu, 2010). The gene discussed is AKT1; the disease is neoplasm.