KGF is a member of the family of fibroblast growth factors and is secreted in large amounts by fibroblast-like stromal cells in epithelial tissues. The KGF receptor encodes a tyrosine kinase and is a member of the family of receptors binding aFGF and bFGF. Binding of KGF to its receptor is competed by aFGF and bFGF. Although KGF is a potent specific mitogen for many epithelial cells it is not so for fibroblasts and endothelial cells. KGF is thought to play an important role in the paracrine growth control of normal epithelial cells. KGF stimulates the proliferation of primary and secondary human keratinocytes to the same extent as EGF.