This gene was identified as a tumor suppressor that is mutated in a large number of cancers at high frequency. The protein encoded this gene is a phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase.

It contains a tensin like domain as well as a catalytic domain similar to that of the dual specificity protein tyrosine phosphatases.

Unlike most of the protein tyrosine phosphatases, this protein preferentially dephosphrylates phosphatidylinositol-3,4,5-trisphosphate in cells and functions as a tumor suppressor by negatively regulating AKT/PKB signaling pathway.