Although the VEGF-A binds to both its receptors (VEGFR-1, VEGFR-2), the primary signaling of endothelial cell proliferation and vascular permeability is mediated by the binding to VEGFR-2, and that is why VEGFA/VEGFR-2 represents the most important ligand-receptor complex necessary for tumor angiogenesis (70). This evidence concerns the gene KDR and neoplasm.