Loss of Estrogen Receptor Beta Expression Correlates with Shorter Overall Survival and Lack of Clinical Response to Chemotherapy in Ovarian Cancer Patients

Background: Estrogen receptor beta (ER beta) belongs to a large family of nuclear receptors. Recent studies have suggested that ER beta in contrast to ER alpha might act as a tumour suppressor in ovarian cancer (OVCA). Materials and Methods: Expression of ER beta was detected by immunocytochemistry in 11 OVCA cell lines and by immunohistochemistry in 43 (41 FIGO stage III) OVCA specimens prepared before chemotherapy and 30 specimens from the same group after chemotherapy. Cisplatin sensitivity in the 11 cell lines was also analysed. Results: No significant correlations between cisplatin-sensitivity and expression of ER beta was found in the cell lines. In the cases which responded well to chemotherapy (complete response) ER beta expression at preliminary laparotomy (PL) was significantly higher (p=0.0004) than in those with progressive disease. Kaplan-Meier analysis revealed that the patients with higher ER)3 expression (>30% of cells) at PL had an increased overall survival time and progression-free time (p=0.00161 and p=0.03255, respectively) than the patients with lower ER beta espression. Significantly shorter overall survival time characterized the cases with lower immunoreactivity score of ER beta expression at secondary cytoreduction (SCR) (p=0.00346). Conclusion: The loss of ER beta expression in ovarian tumours may he a feature of malignant transformation.