KDR and neoplasm: Certain molecules, including vascular endothelial growth factor receptor (VEGFR), integrin αvβ3 [3, 4], somatostatin receptor [5], vasoactive intestinal peptide receptor [6], matrix metalloproteinases [7], E-selectin [8], and CD105 [9], are expressed at higher levels in tumor cells and in newly formed vascular endothelial cells.