Platelet-derived growth factor BB (PDGF-BB) is a member of the PDGF family of growth factors that play a crucial role in cell proliferation, migration, and angiogenesis. PDGF-BB is a homodimeric protein that is released by platelets, macrophages, and endothelial cells in response to tissue injury or inflammation. It acts by binding to its receptors, PDGFR-α and PDGFR-β, leading to the activation of downstream signaling pathways involved in cell growth and tissue repair. PDGF-BB is involved in various physiological processes, such as wound healing, tissue regeneration, and vascular development, as well as in pathological conditions, including fibrosis, atherosclerosis, and cancer.