Consistent with previous observations [22], [30], deletion of PTEN alone does not result in ovarian tumor development (data not shown), suggesting that activation of the phosphatidylinositol-3′ kinase (PI3K) signaling pathway with inactivating PTEN mutations alone may not be sufficient for tumor initiation and needs to act in concert with other oncogenes to cause cancer. Here, PTEN is linked to ovarian neoplasm.