Platelet-derived growth factor (PDGF) is one of the most abundant growth factors contained in the platelet alpha-granules and released upon platelet activation. It is also secreted by epithelial and mesenchymal cells. PDGF family consists of four homodimeric proteins, PDGF-AA, PDGF-BB, PDGF-CC and PDGF-DD, and one heterodimeric protein, PDGF-AB. The PDGFR receptors are encoded by two genes: PDGFRA and PDGFRB. PDGFR is known to control growth, cell movement, angiogenesis and embryo development.