Betacellulin, also known as BTC, belongs to the EGF family of growth factors. It is expressed in many tissues, such as kidney, pancreas and small intestine. Betacellulin is initially synthesized as a membrane-bound precursor containing multiple EGF-like domains in its extracellular region, and is released from the membrane by proteolytic cleavage. BTC is the ligand for EGFR/ErbB receptor tyrosine kinases, and plays a role in cell growth and differentiation. BTC has been reported to promote beta cell growth and differentiation in the pancreas. Pancreas-specific expression of this gene may induce islet neogenesis and remediate hyperglycemia in type I diabetes.