Acting as a phosphatidylinositol-3,4,5 trisphosphate 3-phosphatase, PTEN is a well-described tumor suppressor that deactivates phosphoinositide substrates required for signaling by phosphatidylinositol 3-kinase (PI3K), a key component of the AKT/PKB survival pathway4. The gene discussed is AKT1; the disease is neoplasm.