KDR and renal cell carcinoma: The overall antitumour effects of rapalogues in renal cell carcinoma appear to be more complex with tumour growth inhibition resulting from direct G1/S cell cycle blockage and/or apoptotic effects in carcinoma cells along with the inhibition of downstream signalling of the HIF1α-induced VEGF/VEGFR autocrine loop in endothelial cells shutting down the maintenance of tumour angiogenesis.