May be involved in macrophage-mediated cellular proliferation. It is mitogenic for fibroblasts and smooth muscle but not endothelial cells. It is able to bind EGF receptor/EGFR with higher affinity than EGF itself and is a far more potent mitogen for smooth muscle cells than EGF (By similarity). Plays an important role in the proper development of cranial nerves by inhibiting the migration of the cranial neural crest cells (NCCs) into the odd-numbered neuromeres (r3 and r5) of the hindbrain Plays a role in mediating v-Jun-induced oncogenic transformation. Interacts with CNIH2. Mature HB-EGF is released into the extracellular space and probably binds to a receptor. Expressed uniformly in the embryonic hindbrain. Strongly induced in embryonic fibroblasts transformed by v-Jun.