Altered Apoptosis in Endometriosis Compared with Ovarian Carcinoma

Background and Objectives: Endometriosis has been shown to be associated with an increased cancer risk, and apoptosis may be important in the pathophysiology of endometriosis. To date, it remains unclear whether the tissue cell surface apoptosis marker (annexin V) is an important parameter in terms of cancer and endometriosis. This retrospective study aimed to compare endometriosis cases and ovarian cancer cases in terms of apoptosis and cell proliferation markers' levels. Materials and Methods: In total, 65 (30 ovarian endometrioma, 35 ovarian carcinoma) paraffin blocks were taken for flow cytometric analysis. The flow cytometry analysis markers and annexin V staining levels were compared. Results: The G2/M stage cell ratio, S-phase fraction, proliferative index, aneuploidy cell ratio, and annexin V apoptotic index ratio were found to be statistically significantly lower in the endometrioma group compared to the carcinoma group. However, the G0/G1 phase cell ratio was found to be higher in the endometrioma group. According to the correlation analysis results, annexin V expression level showed a positive correlation with the G2/M cell ratio and S-phase fraction, while it showed a negative correlation with the G0/G1 level. In addition, as the apoptotic index increased, the cell aneuploidy rate also increased, which was statistically significant. When the apoptotic index was used to distinguish between endometrioma and ovarian cancer (cutoff value 16.05%), the sensitivity was found to be 94.3%, and the specificity was found to be 80%, which was statistically significant for cases below the cutoff value to be accepted as endometrioma. Conclusions: Apoptosis was reduced in endometriosis cases. The cell DNA activity was altered in endometriosis cases, as in cancer cases. Flow cytometric analysis can be used in the diagnosis of endometriosis even in paraffin-embedded tissues. The flow cytometric annexin V analysis provided results in an average of 30 min, making it a promising and highly sensitive differential diagnostic marker to distinguish between endometriosis and ovarian cancer.