PTEN (phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase) contains a tensin-like domain as well as a catalytic domain similar to that of the dual specificity protein tyrosine phosphatases. It was identified as a tumor suppressor that is mutated in a large number of cancers, including sporadic brain, breast, endometrial, kidney, and prostate cancers.