Fibroblast Growth Factor
A fibroblast is a "connective-tissue cell of mesenchymal origin that secretes proteins and especially molecular collagen from which the extracellular fibrillar matrix of connective tissue forms".

FGFs initiate fibroblast proliferation. The original FGF molecule (now known as FGF-2 or FGF basic ) also induces proliferation of endothelial cells, chondrocytes, smooth muscle cells, and melanocytes.