Description: PDGF-BB is a member of the platelet-derived growth factor family, a group of proteins that are released by platelets upon activation. The PDGF proteins are dimers of two of four peptide chains designated A, B, C, and D. PDGF-BB is formed by two B-chains, while PDGF-AB is one B chain and one A-chain forming the only heterodimer in the family. PDGF-BB is unique among the family in that it can bind to and activate all three forms of the PDGF receptor. It induces the proliferation, migration, and survival of fibroblasts, endothelial cells, epithelial cells, and smooth muscle cells. PDGF-BB is important for angiogenesis and smooth muscle formation during embryonic development, and plays a role in wound healing and regeneration in adults. High levels of PDGF-BB are often detected in malignant tumors, and it is believed to facilitate tumor metastasis and vascularization.