Human Epidermal growth factor (EGF) and TGFα, Vaccinia growth factor, amphiregulin belong to the same family and can bind to the same 170KDa receptor. EGF is a 130KDa precursor when it is first synthesized, and the mature protein has only 54 amino acids and a molecular weight of 6KDa. EGF can promote the growth and differentiation of various cells and tissues, such as epithelial differentiation, vascular regeneration, mesenchymal growth, etc.