KDR and renal cell carcinoma: Currently, there are five angiogenesis inhibitors approved by the United States Food and Drug Administration for treatment of advanced and metastatic RCC, four VEGFR2 targeted tyrosine kinase inhibitors (TKIs), including sorafenib, sunitinib, axitinib and pazopanib, and one anti-VEGF monoclonal antibody, bevacizumab27, 28, 29, 30, 31.