FGF5 is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. This gene was identified as an oncogene, which confers transforming potential when transfected into mammalian cells. Targeted disruption of the homolog of this gene in mouse resulted in the phenotype of abnormally long hair, which suggested a function as an inhibitor of hair elongation. Alternatively spliced transcript variants encoding different isoforms have been identified.