Fibroblast growth factor 8e （FGF-8e）, a secreted heparin-binding protein, is a member of the fibroblast growth factor （FGF） family and is an isoform of FGF-8. Alternative splicing of fgf-8 gene gives rise to potentially four （a, b, e, f） different protein isoforms in human. FGF-8 is widely expressed during embryogenesis, and mediates epithelial-mesenchymal transitions. It plays an organizing and inducing role during gastrulation, and regulates patterning of the midbrain/hindbrain, eye, ear, limb and heart in the embryo.