PDGF (Platelet-derived growth factor) is one among numerous growth factors that regulate cell growth and division. The PDGF family forms five dimeric ligands, PDGF-AA, PDGF-BB, PDGF-CC, PDGF-DD, and PDGF-AB, which activate cognate receptor tyrosine kinases PDGFR-α and PDGFR-β. Upon binding to its tyrosine kinase receptor PDGF-αα, PDGF-AA stimulates the proliferation of osteoblastic cells and may exert autocrine and paracrine effects in regulating bone-forming processes. PDGF-AA is the most well characterized mitogen that is not restricted to any kind of tumor cell type but was seen in osteoblastic cells as well as in pleomorphic tumor elements.

> 90% as determined by Bis-Tris PAGE