Objective: To fi nd out any relationship between presence of P450 aromatase and estrogen (ER) and progesteron (PR) receptors in eutopic endometrium of women with and without endometriosis and in estrogen-dependent gynecologic lesions (endometrial hyperplasia and endometriosis). Design: Retrospective study. Setting: Šikl’s Institute of Pathology, Department of Gynecology and Obstetrics, University Hospital and Medical Faculty in Pilsen, Charles University. Methods: The examined samples were obtained from patients of Department of Gynecology and Obstetrics, University Hospital and Medical Faculty in Pilsen (2001-2002) and elaborated in Šikl’s Institute of Pathology, University Hospital and Medical Faculty in Pilsen. There were four experimental groups: endometrial hyperplasia, endometriosis and eutopic endometrium of women with and without endometriosis. P450 arom, ER and PR were detected by using immunohistochemical methods with specifi c antibodies. Results: P450 aromatase was detected in a higher amount in endometriosis, hyperplasia and some samples of metaplasia. Estrogen and progesterone receptors were detected in all examined tissues. Number and spreading of ER and PR depend on the phase of the cycle. Lower number of ER was found in atrophic and metaplastic endometrium and in atypic hyperplasia. There was not found any direct relationship between presence of P450 aromatase and both types of receptors. Conclusion: Steroid metabolism in examined pathologically changed tissues is due to molecular aberrations regulated on the local level. It is not possible to use detection of P450 aromatase as a diagnostic test for pelvic endometriosis.

        Key words: P450 aromatase, estrogen and progesterone receptors, immunohistochemistry, endometrium, endometriosis, endometrial hyperplasia