KDR and neoplasm: Toceranib acts by blocking the function of several receptors on the surface of tumor cells, as well as on the surface of new blood vessels including vascular endothelial growth factor receptor 2 (VEGFR2), platelet derived growth factor receptor (PDGFR), and stem cell factor receptor (KIT), permitting it to have effects on both the tumor as well as the tumor microenvironment (vasculature, etc.)[1-5].