Despite frequent PTEN (phosphatase and tensin homologue) loss and Akt/mammalian target of rapamycin (mTOR) signaling in prostate cancer, the disease is insensitive to single-agent mTOR inhibition. Insulin-like growth factor-1 receptor inhibition might mitigate the feedback inhibition by Torc1 inhibitors, suppressing downstream Akt activation and, thus, potentiating the antitumor activity of mTOR inhibition.