Since VEGFR2 is over expressed in tumor vasculature (40,000 copies/endothelial cell) and has a high binding affinity (Ka = 5 to 77×1014 M−1) to VEGF [22], VEGF receptors have been targeted as anti- and pro-angiogenic therapeutic agents as well as angiogenesis mediator based imaging agents [23], [24]. Here, KDR is linked to neoplasm.