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Epidermal growth factor （EGF） has been localized in human salivary and Brunner's glands and found to stimulate the proliferation of gastrointestinal and pancreatic tissues in animals, is a single polypeptide of 53 amino acid residues which is involved in the regulation of cell proliferation. EGF exerts its effects in the target cells by binding to the plasma membrane located EGF receptor. And The EGF receptor is a transmembrane protein tyrosine kinase. EGF is also a peptide which effects the growth and/or differentiated functions of many cell types. Several pieces of evidence indicate that EGF and its receptor may play a role in carcinogenesis.