KDR and neoplasm: It inhibits the activity of serine/threonine kinases of RAF, protein kinases of MEK and ERK, and blocks vascular endothelial growth factor receptors (VEGFR), platelet-derived growth factor receptors (PDGFR), the cytokine receptor c-KIT, and the receptor tyrosine kinase Flt-3 to inhibit tumor angiogenesis and tumor cell growth [4-6].