Influence of goserelin depot therapy on epidermal growth factor receptor expression in pelvic endometriosis

We have studied epidermal growth factor (EGF) receptor expression in endometrium and in endometriotic implants, testing a group of 36 women before and after a 4-month gonadotropin-releasing hormone (GnRH) analog (GnRH-a) goserelin depot treatment. Each woman underwent laparoscopy twice. At the initial laparoscopy, before starting treatment, the disease was staged according to the American Fertility Society (AFS) classification and biopsies of endometriotic implants were undertaken. The follow-up laparoscopy was performed within 5 weeks of the last GnRH-a administration. Biopsies were taken from areas of previously noted disease, both visually persistent and visually free of disease. At the time of each laparoscopy, photographs of all areas of disease were taken. Specimens of eutopic endometrium were collected from each patient at the time of laparoscopy by a Novak curette. Endometrial and endometriotic samples were processed for immunohistochemical detection of EGF receptor, using anti-EGF receptor monoclonal antibody Ab-3. After treatment, the marked improvement of AFS score was associated with a dramatic reduction of EGF receptor immunostaining, but the exact meaning of this finding is still not completely understood. The dramatic reduction of EGF receptor expression in eutopic and ectopic endometrium samples after treatment is not obviously related to the hypoestrogenism induced by the drug. It has been suggested that steroid hormones and EGF play a role in regulation of EGF receptor expression, so that drugs such as goserelin depot could act directly at local peripheral level influencing the EGF receptor expression via the production of its ligand.