In this report we studied the cellular inhibitor of PP2A, SET (I2PP2A), to further understand (1) its expression patterns in prostate cancer progression, (2) its regulatory role in prostate cancer, (3) whether SET can regulate PI3K signaling and (4) if targeting SET can be exploited as a therapeutic for treatment of Pten deficient prostate cancers. This evidence concerns the gene SET and Familial prostate cancer.