ErbB4/HER4 is a receptor tyrosine kinase that belongs to the human epidermal growth factor receptor (EGFR) family. ErbB4 is ubiquitously expressed with the highest expression occurring in brain and heart. Proteolytic cleavage of ErbB-4 is promoted by the binding of heregulin. The expression of ErbB4 in breast cancer, pediatric brain cancer and other types of carcinomas has been reported in research studies suggesting that ErbB4 expression is involved in both normal tissue development and carcinogenesis.
