Comparison of Ki-67 proliferative index between eutopic and ectopic endometrium: a case control study

OBJECTIVE: In this study, the Ki-67 proliferative indices among the stages of the endometriosis were compared to clarify whether the proliferation was increased with increasing disease stage. MATERIALS AND METHODS: Thirty-eight patients who underwent surgery either by laparotomy or by laparoscopy with the diagnosis of endometriosis and 21 patients, as controls, who underwent hysterectomy with the diagnosis of myoma uteri and without any endometrial pathology at our hospital between 2005 and 2007 were studied. Biopsy specimens of endometriotic foci and endometriomas in study group, and eutopic endometrium of hysterectomy specimens of control group were studied. RESULTS: Fifty-nine patients were divided into Group 1 (21 patients in control), Group 2 (19 patients in stage I and II of endometriosis), and Group 3 (19 patients in stage III and IV). A moderate correlation between the stage of endometriosis and the degree of Ki-67 staining was found. When Ki-67 immunohistochemical staining was considered according to the threshold value for CA-125 (35 U/mL), Ki-67 positivity was increased with the increase in CA-125 value, but this increase was not statistically significant. CONCLUSION: Endometriosis shows some characteristics of tumors such as high rate of invasion, getting autonomy, and proliferation as the disease progresses with subsequent damage to target organs. When the stage of the disease increases, environment becomes more suitable for increased proliferation and invasion. In this study, the increase in proliferative activity as the severity increases is shown by the increase in Ki-67 index. As more studies are being conducted in this field, pathogenesis will be clarified, which could help in the development of new treatment modalities.