Fibroblast Growth Factor 7 (FGF-7), also known as Keratinocyte Growth Factor (KGF), is a potent mitogen that regulates epithelial cell migration and differentiation. FGF-7 is produced by mesenchymal cells and binds in high affinity to a splice variant of FGF receptor 2 (FGFR2-IIIb). The mitogenic activity of FGF-7 acts predominantly on keratinocytes, but not on fibroblast or endothelial cells. FGF-7 expression is upregulated after acute and chronic injury, suggesting that FGF-7 functions during the healing of injured epithelial cells. FGF-7 also induces the formation of the apical ectoderm ridge during limb development.