KDR and renal cell carcinoma: Sorafenib is a multikinase inhibitor affecting transmembrane VEGFR-2, VEGFR-3, FLT-3, PDGFR-B and KIT receptors, as well as intracellular serine/threonine-protein kinase B-raf (BRAF) and RAF proto-oncogene serine/threonine-protein kinase (CRAF) receptors, which is used in the treatment of patients with RCC [38].