Epidermal Growth Factor and Its Receptor and Their Possible Relationships to Gynecologic Endocrinology

Abstract

Recent research in endocrinology is beginning to show that paracrine chemical substances such as epidermal growth factor may play important roles in fostering differentiation of epithelia, including tissues in the reproductive tract, raising implications for the understanding of hormone responsiveness and oncogenesis. The current enthusiasm for the study of peptide growth factors,¹ epidermal growth factor (EGF), and their cell-surface receptors, is based on the realization that most of them have mitogenic properties and regulate a cascade of events (pleiotropic response) in normally dividing cells. On the other hand, cells that are transformed (after exposure to retroviruses) produce proteins that have extensive primary sequence homology with these peptide growth factors, thus becoming independent of an exogenous supply of mitogens required for their growth. EGF and other peptide growth factors exert their biologic effect through specific receptor proteins located at the plasma membrane. An exciting discovery was made when the primary structure of the EGF receptor was determined and was compared with a data base of all known protein sequences.^2–4 Extensive homology was found between the EGF receptor and the protein encoded by a viral oncogene (erbB);oncogenes are genomic sequences in the cellular or viral genome that are considered responsible for the induction of neoplasia