Feline Platelet-Derived Growth Factor-BB (PDGF-BB) is a homodimeric growth factor composed of two PDGF-B chains that plays a key role in cell proliferation, migration, angiogenesis, and tissue repair in cats (Felis catus). PDGF-BB signals primarily through the PDGF receptor-β (PDGFR-β) and PDGFR-α/β receptor complexes, activating downstream signaling pathways including PI3K/AKT, MAPK, and STAT, which regulate fibroblast activation, smooth muscle cell proliferation, and extracellular matrix production. In cats, PDGF-BB is produced by platelets, macrophages, endothelial cells, and fibroblasts, and is released during tissue injury, inflammation, and wound healing. It plays important roles in dermal repair, vascular remodeling, and connective tissue regeneration, supporting healing of skin wounds and surgical sites. PDGF-BB signaling is also implicated in fibrotic processes and tumor biology, including feline fibrosarcoma and other mesenchymal tumors, where PDGF-driven cell proliferation and stromal interactions can influence tumor growth and tissue remodeling. Because of its central role in regulating cell growth, angiogenesis, and tissue regeneration, feline PDGF-BB is studied in research on wound healing, fibrosis, cancer biology, and regenerative medicine, contributing to improved understanding of tissue repair mechanisms and disease processes in cats.