Oestrogen receptors (ESRs) regulate the growth and differentiation of normal ovarian epithelia. However, to date their role as biomarkers in the clinical setting of ovarian cancer remains unclear. In view of potential endocrine treatment options, we tested the role of ESR1 mRNA expression in ovarian cancer in the context of a neo-adjuvant chemotherapy trial. Study participants had epithelial ovarian or peritoneal carcinoma unsuitable for optimal upfront surgery and were treated with neo-adjuvant platinum-based chemotherapy before surgery. RNA was isolated from frozen tumour biopsies before treatment. RNA expression of ESR1 was determined by microarray and reverse transcriptase kinetic PCR technologies. The prognostic value of ESR1 was tested using univariate and multivariate Cox proportional hazards models, Kaplan–Meier survival statistics and the log-rank test. ESR1 positively correlates with proliferation markers and histopathological grading. ESR1 was a significant predictor of survival as a continuous variable in the univariate Cox regression analysis. In multivariate analysis, elevated baseline ESR1 mRNA levels predicted prolonged progression-free survival (P=0.041) and overall survival (P=0.01) after neo-adjuvant chemotherapy, independently of pathological grade and age. We conclude that pretreatment ESR1 mRNA is associated with tumour growth and is a strong prognostic factor in ovarian cancer, independent of the strongest clinical parameters used in clinical routine. We suggest that ESR1 mRNA status should be considered in order to minimize possible confounding effects in ovarian cancer clinical trials, and that early treatment with anti-hormonal agents based on reliable hormone receptor status determination is worth investigating.
Claudio Zamagni, Ralph M Wirtz, Pierandrea De Iaco, Marta Rosati, Elke Veltrup, Federica Rosati, Elisa Capizzi, Nicoletta Cacciari, Carlo Alboni, Alessandra Bernardi, Francesco Massari, Sara Quercia, Antonietta D'Errico Grigioni, Manfred Dietel, Jalid Sehouli, Carsten Denkert and Andrea Angelo Martoni
Silvia Darb-Esfahani, Ralph M Wirtz, Bruno V Sinn, Jan Budczies, Aurelia Noske, Wilko Weichert, Areeg Faggad, Susanne Scharff, Jalid Sehouli, Guelten Oskay-Özcelik, Claudio Zamagni, Pierandrea De Iaco, Andrea Martoni, Manfred Dietel and Carsten Denkert
Epidemiological and cell culture studies indicate that ovarian carcinoma growth is dependent on estrogen stimulation. However, possibly due to the lack of a reliable biomarker that helps to select patients according to prognostically relevant estrogen receptor (ER) levels, clinical trials using anti-estrogenic therapeutics in ovarian carcinoma have had inconsistent results. Therefore, we tested if ER expression analysis by a quantitative method might be useful in this regard in formalin-fixed paraffin-embedded (FFPE) tissue. In a study group of 114 primary ovarian carcinomas expression of estrogen receptor 1 (ESR1) mRNA was analyzed using a new method for RNA extraction from FFPE tissue that is based on magnetic beads, followed by kinetic PCR. The prognostic impact of ESR1 mRNA expression was investigated and compared to ERα protein expression as determined by immunohistochemistry. In univariate survival analysis the expression level of ESR1 mRNA was a significant positive prognostic factor for patient survival (hazard ratio (HR) 0.230 (confidence interval (CI) 0.102–0.516), P=0.002). ERα protein expression was correlated to ESR1 mRNA expression (P=0.0001); however, ERα protein expression did not provide statistically significant prognostic information. In multivariate analysis, ESR1 mRNA expression emerged as a prognostic factor, independent of stage, grade, residual tumor mass, age, and ERα protein expression (HR 0.227 (CI 0.078–0.656), P=0.006). Our results indicate that the determination of ESR1 levels by kinetic PCR may be superior to immunohistochemical methods in assessment of biologically relevant levels of ER expression in ovarian carcinoma, and is feasible in routinely used FFPE tissue.