PTEN is a dual-specificity protein phosphatase, dephosphorylating tyrosine-, threonine- and serine-phosphorylated proteins. PTEN has also a lipid phosphatase activity that is critical for its tumor suppression function. PTEN antagonizes the PI3K-AKT/PKB signaling pathway by dephosphorylating phosphoinositides and thereby modulating cell cycle progression and cell survival. Defects in PTEN are the cause of numerous cancers such as in Cowden disease (breast, thyroid and skin cancer predisposition), Lhermitte-Duclos disease, and head and neck squamous cell carcinoma.The synthetic peptide used to raise the antibody Cat. No. 200145 is selected from a sequence within the N-term region of human PTEN. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.