Immunohistochemical localization of insulin-like growth factor-binding protein-3 in eutopic and ectopic endometrial tissues

Objective: To evaluate the expression of insulin-like growth factor–binding protein-3 (IGFBP-3) in the eutopic endometrium and in endometriotic lesions.

Design: Retrospective immunohistochemical study.

Patient(s): Twenty-five normal women and 39 women with endometriosis.

Intervention(s): Endometrial and endometriotic tissue biopsies obtained at laparoscopy.

Main Outcome Measure(s): Expression of IGFBP-3 assessed by immunohistochemistry.

Result(s): In the endometrium, positive immunostaining of IGFBP-3 was observed both in the stroma and the epithelial glands. The intensity of staining in the glands during the secretory phase was significantly higher in women with endometriosis compared with controls (P=.018). An increased expression of IGFBP-3 over controls was found in stages I and II of the disease (P=.018), whereas in stages III and IV, the difference between controls and women with endometriosis was not significant (P=.300). In endometriotic tissues, a much-marked immunostaining of IGFBP-3 was noted in 90% of the glands and 67% of the stroma without apparent differences related to cycle phase.

Conclusion(s): These data show intense staining of IGFBP-3 in endometriosis lesions and increased expression of the protein in the endometrium of patients with endometriosis compared to controls. This marked expression of IGFBP-3 could be related to its previous finding in the peritoneal fluid and to its potential involvement in the pathophysiology of endometriosis.