Heparin-Binding Epidermal Growth Factor-like growth factor (HB-EGF) is a member of the Epidermal Growth Factor (EGF) family and is expressed by monocytes and macrophages. HB-EGF is the predominant growth factor involved in epithelialization during wound healing. HB-EGF signals through the receptor tyrosine kinase ErbB2 to maintain adult heart homeostasis and promotes cardiac valve development through binding in high affinity to the epidermal growth factor receptor (EGFR). HB-EGF binds the the ErbB4 receptor tyrosine kinase to mediate implantation of the human blastocyst. HB-EGF also functions as a potent mitogen for fibroblasts and smooth muscle cells.