Significance of Endocan Expression in Various Types of Epithelial Ovarian Tumors

Ovarian cancer is associated with the highest mortality rate among gynecologic malignancies. Despite new therapeutic strategies, ovarian cancer still has a high risk of metastasis and mortality. Endocan is a newly identified endothelial cell activation marker, which is responsible for angiogenesis, tumor invasion, and aggressive behavior of tumors. The aim of this study was to assess Endocan expression in different types of ovarian tumors and to identify its relationship with clinicopathologic characteristics of ovarian tumors.

This cross-sectional study was conducted on 183 tissue samples, including benign, borderline, and malignant ovarian tumors collected from the University Kebangsaan Malaysia Medical Center archive of Pathology during 2005-2015. Mouse monoclonal anti-human Endocan/ESM-1 Clone MEP08 was used at a dilution of 1:400 for immunohistochemical (IHC) staining. All the information was collected by a checklist, and the association between clinicopathological features and high or low levels of Endocan -MVD was evaluated using Pearson chi-square, Fischer's exact, or Monte Carlo tests.

The prevalence of Endocan positivity was significantly higher in malignant compared to borderline and benign ovarian tumors (P<0.001). There was also a significant association between type of tumor and Endocan status in malignant ovarian tumors (P=0.02), indicating that Endocan positivity was more likely in serous malignant ovarian tumors compared to other ovarian tumor types. However, the tumor stage was not significantly associated with Endocan status (P=0.31).

This study showed that Endocan positivity may show the highest prevalence among malignant tumors suggesting that high Endocan expression would be negatively associated with ovarian tumor behavior.