VEGF is one of the key regulators of angiogenesis, vasculogenesis, and developmental hematopoiesis. It is a mitogen and survival factor for vascular endothelial cells while also promoting vascular endothelial cell and monocyte motility. Binding of growth factors to the ectodomain of their transmembrane receptors leads to receptor dimerization, protein kinase activation, trans-autophosphorylation, and initiation of signaling pathways. The VEGF family of receptors (RTK class IV, VEGF receptor family) consists of three protein–tyrosine kinases (VEGFR1, VEGFR2, and VEGFR3) and two non-protein kinase co-receptors (neuropilin-1 and 2). Targeting VEGF receptors proved to be a successful therapeutic approach for disorders with non-physiologic angiogenesis including age-related macular degeneration of the eye, diabetic retinopathy, rheumatoid arthritis, tumor growth and metastasis1.