Betacellulin (BTC), a member of the epidermal growth factor (EGF) family, was originally isolated from mouse beta cell tumor (betaTC-3) as a growth–promoting factor and is known to be expressed in pancreatic α-cells, β-cells, and duct cells in adult humans. BTC acts through binding to four ErbB tyrosine kinase receptors (EGF-R/ErbB-1, neu/ErbB-2, ErbB-3, and ErbB-4).
