This gene encodes a secreted peptide hormone and member of the epidermal growth factor (EGF) family of proteins. The encoded protein is a ligand of the epidermal growth factor receptor (EGFR) and the structurally related erb-b2 receptor tyrosine kinase 4 (ERBB4). The encoded protein may be involved in a wide range of biological processes including inflammation, wound healing, oocyte maturation, and cell proliferation. Additionally, the encoded protein may promote the progression of cancers of various human tissues.