PTEN (phosphatase and tensin homologue deleted on chromosome ten), also referred to as MMAC (mutated in multiple advanced cancers) phosphatase, is a tumor suppressor implicated in a wide variety of human cancers. PTEN encodes a 403 amino acid polypeptide originally described as a dual-specificity protein phosphatase. The main substrates of PTEN are inositol phospholipids generated by the activation of the phosphoinositide 3-kinase (PI3K). PTEN is a major negative regulator of the PI3K/Akt signaling pathway . PTEN possesses a carboxy-terminal, noncatalytic regulatory domain with three phosphorylation sites (Ser380, Thr382, and Thr383) that regulate PTEN stability and may affect its biological activity . PTEN regulates p53 protein levels and activity and is involved in G protein-coupled signaling during chemotaxis.