Epidermal growth factor, from gene organization to bedside

•Submaxillary gland and kidney are predominant source of EGF production.•EGF/EGFR signaling promotes embryonic development and stem cell regeneration and regulates ion transport.•EGF plays pivotal role in ulcer/wound healing.•Dysregulation of EGF expression may contribute to the cancer development. In 1962, epidermal growth factor (EGF) was discovered by Dr. Stanley Cohen while studying nerve growth factor (NGF). It was soon recognized that EGF is the prototypical member of a family of peptide growth factors that activate the EGF receptors, and that the EGF/EGF receptor signaling pathway plays important roles in proliferation, differentiation and migration of a variety of cell types, especially in epithelial cells. After the basic characterization of EGF function in the first decade or so after its discovery, the studies related to EGF and its signaling pathway have extended to a broad range of investigations concerning its biological and pathophysiological roles in development and in human diseases. In this review, we briefly describe the gene organization and tissue distribution of EGF, with emphasis on its biological and pathological roles in human diseases.