Growth factor for endothelial cells. VEGF-B167 binds heparin and neuropilin-1 whereas the binding to neuropilin-1 of VEGF-B186 is regulated by proteolysis (By similarity). Homodimer; disulfide-linked. Can also form heterodimer with VEGF (By similarity). Secreted but remains associated to cells or to the extracellular matrix unless released by heparin. Additional isoforms seem to exist. Belongs to the PDGF/VEGF growth factor family.