Cowden disease is an autosomal dominant inherited cancer syndrome characterized by the occurrence of multiple hamartomas, tumors or hyperplastic lesions that may develop in any organ. The disease is related to germline mutation of the PTEN gene, a recently cloned tumor suppressor gene involved in the pathogenesis of sporadic glioblastoma and endometrial carcinoma. It has been shown that the PTEN gene product was a phosphatase able for dephosphorylating a lipid substrate: the phosphatidylinositol (3,4,5)-triphosphate (PIP3). So PTEN appears to negatively control the PI3K-AKT signaling pathway implicated in regulation of cell growth and survival.