Epidermal growth factor - EGF is a growth factor that plays an important role in the regulation of cell growth, proliferation, and differentiation by binding to its receptor EGFR. EGF is the founding member of the EGF-family of proteins. Members of this protein family have highly similar structural and functional characteristics. Besides EGF itself, other family members include:Heparin-binding EGF-like growth factor (HB-EGF), transforming growth factor-alpha (TGF-alpha),Amphiregulin (AR), Epiregulin(EPR), Epigen, Betacellulin (BTC), neuregulin's (NRG's).