VEGF-D belongs to the VEGF/PDGF family of proteins. VEGF-D promotes lymphangiogesis,endothelial cell growth,and regulates vascular permeability. In addition,VEGF-D has an important part in the creation of the venous and lymphatic vascular systems and in the growth and maintenance of differentiated lymphatic endothelium Mature VEGF-D forms a noncovalently linked homodimer,and binds to and activate both VEGFR-2 (flk1) and VEGFR-3 (flt4).