Description
HER4 or ERBB4 is a transmembrane receptor tyrosine kinase that belongs to epidermal growth factor receptor family (1). Through its interaction with its activating ligand heregulin, HER4 can regulate proliferation and differentiation of cells (2). HER4 ectodomain is cleaved by a metalloprotease, gamma-secretase that releases the HER4 intracellular domain from the membrane and facilitates its translocation to the nucleus. The kinase activity of HER4 is both necessary and sufficient to trigger an antiproliferative response in human breast cancer cells. Increased expression of HER4 has been detected in various cancers and this usually correlates to better survival