PTEN encodes a lipid phosphatase that dephosphorylates phosphatidylinositol (3,4,5)- triphosphate (PIP3) to oppose the activity of phosphatidylinositol 3-kinase (PI3K), which functions as a PIP3 kinase that is constitutively activated and functions as an oncogene in many cancer types [16]. Here, PTEN is linked to cancer.