Canine Platelet-Derived Growth Factor-BB (PDGF-BB) is a homodimeric growth factor composed of two PDGF-B chains that plays a central role in cell proliferation, migration, angiogenesis, and tissue repair in dogs (Canis lupus familiaris). PDGF-BB signals primarily through platelet-derived growth factor receptor-β (PDGFR-β) and PDGFR-α/β receptor complexes, activating intracellular signaling pathways including PI3K/AKT, MAPK, and STAT, which regulate fibroblast activation, smooth muscle cell proliferation, and extracellular matrix production. In dogs, PDGF-BB is produced by platelets, macrophages, endothelial cells, fibroblasts, and other stromal cells, and is released during tissue injury, inflammation, and wound healing. It plays important roles in dermal repair, vascular remodeling, and connective tissue regeneration, contributing to healing of skin wounds, surgical sites, and musculoskeletal injuries. PDGF-BB signaling is also implicated in fibrotic processes and tumor biology, including canine fibrosarcoma, osteosarcoma, and mast cell tumors, where PDGF-driven signaling can promote tumor cell proliferation and tumor microenvironment remodeling. Because of its involvement in angiogenesis, tissue regeneration, and cellular growth signaling, canine PDGF-BB is widely studied in research on wound healing, regenerative medicine, fibrosis, and cancer biology, with relevance to both veterinary treatment strategies and comparative oncology.