MTOR and liver cancer: mTOR signaling that regulates cell growth, proliferation and survival is frequently activated in many tumors including RCC.19, 20, 21 Our data suggest that HPIP activates mTOR signaling in RCC cells which is consistent with our previous findings in liver cancer.6 In our published work, we demonstrate that HPIP controls mTOR signaling by a cooperative mechanism involving both modulation of mTOR phosphorylation and mTOR expression.