PTEN and posterior cortical atrophy: Inactivation of PTEN (phosphatase and tensin homologue) by deletion or mutation has been identified in ~20% of primary PCa and approximately 35% of CPRC cases (Fig. 1a).380 PTEN, a dual-specificity phosphatase, converts phosphatidylinositol-3,4,5-trisphosphate (PIP3) into phosphatidylinositol 4,5-bisphosphate (PIP2),381 causing PTEN to function as a direct antagonist of the activity of class I PI3K, which converts PIP2 to PIP3.