MTOR and renal cell carcinoma: Mammalian Target of Rapamycin (mTOR) kinase, which regulates cell growth, survival, invasion and metastasis, is a critical player in tumorigenesis and progression.11 As HPIP has been shown to activate mTOR signaling in liver cancer cells,6 we investigated whether activation of mTOR signaling is responsible for HPIP modulation of RCC cell proliferation and migration.