KDR and renal cell carcinoma: Sorafenib, a vascular endothelial growth factor receptor–tyrosine kinase inhibitor (VEGFR-TKI), was approved as a first-in-class molecular-targeted drug for patients with unresectable and recurrent renal cell carcinoma (RCC) due to the extension of progression-free survival (PFS) in a phase 3 study [1].