High expression levels of cyclin B1 and Polo-like kinase 1 in ectopic endometrial cells associated with abnormal cell cycle regulation of endometriosis

ObjectiveTo investigate the possible roles of cyclin B1/cyclin-dependent kinase (cdc2) and Polo-like kinase 1 (Plk1) in the pathogenesis of endometriosis.DesignA case-control study.SettingUniversity hospital.Patient(s)Patients with or without endometriosis were diagnosed by pathological examination or laparoscopy. The patients with the following criteria within the past 6 months were excluded: endocrine or inflammatory diseases, pregnancy or lactation, hormonal therapy, and neoplasm in the uterine cavity.Intervention(s)Eutopic and ectopic endometria were obtained at the time of surgery. Blood was collected on the same day as surgery.Main Outcome Measure(s)The mRNA/protein expression and localization of cyclin B1, cdc2, and Plk1 in endometrium, and serum levels of E2 and P.Result(s)The expression levels of cyclin B1 and Plk1, but not cdc2, in ectopic endometria were significantly higher than in eutopic endometria. The immunohistochemical staining of cyclin B1 and Plk1 was detected in the nuclei of ectopic and eutopic endometrial cells. Furthermore, ectopic endometrial expression levels of cyclin B1 or Plk1 were positively correlated with serum E2 levels.Conclusion(s)Cyclin B1 and Plk1 may play important roles in the pathogenesis of endometriosis by mediating ectopic endometrial cell proliferation under regulation of ovarian hormones.