Expression of 17beta-hydroxysteroid dehydrogenase type 2 in pelvic endometriosis

Lack of expression or a deficiency of 17beta-hydroxysteroid dehydrogenase type 2 (17beta-HSD2), a key enzyme in estradiol inactivation, could be involved in the pathophysiology of endometriosis. The aim of the present study was to evaluate expression of the gene (17beta-Hsd2) encoding 17beta-HSD2 in eutopic and ectopic endometrial tissues of women with endometriosis. Thirty-four infertile women were divided into a control group, without any clinical or laparoscopic evidence of endometriosis (n = 19), and a group with pelvic endometriosis (n = 15). Diagnosis was confirmed by histological examination of the endometriotic lesions. 17beta-Hsd2 mRNA expression was detected by reverse transcription-polymerase chain reaction in the control group (54% of the samples), in the eutopic endometrium of patients with endometriosis (83% of the specimens analyzed) and in all endometriotic lesions. The semi-quantitative analysis of 17beta-Hsd2 mRNA showed a significantly higher gene expression in the endometriotic implants compared with the intrauterine endometrium of the control group (p < 0.05). 17beta-HSD2 protein was localized to the glandular epithelium of both eutopic endometrium and endometriotic implants. The present results refute the hypothesis of lower or absent 17beta-HSD2 expression in pelvic endometriosis; therefore further studies are needed to assess other potential mechanisms leading to increased estrogenic activity within endometriotic implants.