Expression of the cyclin-dependent kinase inhibitor p27(Kip1) in eutopic endometrium and peritoneal endometriosis

Objective: This study was undertaken to evaluate the immunohistochemical ex pression of the cell cycle inhibitor p27(Kip1) and proliferation marker Ki6 7 in peritoneal endometriosis and eutopic endometrium. Design: Prospective study. Setting: University hospital. Patient(s): Thirty-one patients with peritoneal endometriosis. Intervention(s): During laparoscopy, 25 samples of predominantly red perito neal lesions and 27 samples of predominantly black peritoneal lesions were collected from 31 patients with endometriosis. Eutopic endometrium from 25 patients with endometriosis was collected by curettage during laparoscopy o r just after surgery. Main Outcome Measure(s): The percentage of glandular and stromal cells exhi biting positive staining for p27(Kip1) and Ki67 (labeling index, LI) was de termined. Result(s): The LI of stromal cells in red peritoneal lesions for both p27(K ip1) and Ki67 was similar to that of proliferative eutopic endometrium. Alt hough the LI of glandular epithelial cells for Ki67 in red lesions was comp arable to that of proliferative eutopic endometrium, the LI for p27(Kip1) w as significantly higher. Furthermore, we detected a significantly higher LI of glandular epithelial and stromal cells for p27(Kip1) in black lesions c ompared with red lesions. Conclusion(s): Our results suggest that expression of the cyclin kinase inh ibitor p27(Kip1) is involved in the natural history and progression of peri toneal endometriosis. (Fertil Steril(R) 2001;75:956-60. (C)2001 by American Society for Reproductive Medicine.).