Human vascular endothelial growth factor (VEGF 165) is produced as a homodimer. It binds to the FLT1/VEGFR1 and KDR/VEGFR2 receptors, heparan sulfate and heparin. VEGF 165 is a specific mitogen for vascular endothelial cells and a strong angiogenic factor in vivo. In addition to its action as a mitogen it is a potent vascular permeability factor (VPF) in vivo. It is also a chemoattractant molecule for monocytes and endothelial cells. It induces endothelial cell proliferation, promotes cell migration, inhibits apoptosis and induces permeabilization of blood vessels.