Estrogen receptor 1 mRNA is a prognostic factor in ovarian carcinoma: determination by kinetic PCR in formalin-fixed paraffin-embedded tissue

Abstract

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 formalinfixed 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 ERa 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), PZ0.002). ERa protein expression was correlated to ESR1 mRNA expression (PZ0.0001); however, ERa 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 ERa protein expression (HR 0.227 (CI 0.078-0.656), PZ0.006). 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.

Oestrogen receptor 1 mRNA is a prognostic factor in ovarian cancer patients treated with neo-adjuvant chemotherapy: determination by array and kinetic PCR in fresh tissue biopsies

“…Interestingly, pretreatment ESR1 mRNA expression was not related to the response to neoadjuvant chemotherapy. Based on our observation, a validation study was performed on an independent cohort of 114 patients treated with platinum-based adjuvant chemotherapy after surgery for stages I-IV ovarian carcinoma (Darb-Esfahani et al 2009). This study confirmed in a different clinical setting the relevance of ESR1 mRNA expression as a prognostic factor.…”

“…The prognostic value of ESR1 was further validated in formalin-fixed paraffin-embedded tissue samples from an independent population-based cohort of ovarian cancer patients. Data on ESR1 expression from fresh tissue analysis are presented in this article, while data from fixed tissue analysis are presented in the preceding article published in this issue of the journal (Darb-Esfahani et al 2009). …”

An online survival analysis tool to rapidly assess the effect of 22,277 genes on breast cancer prognosis using microarray data of 1,809 patients

“…However, in this case the expression should be confirmed by independent methods like RT-PCR or immunhistochemistry to achieve a reliable correlation. Such a fine-tuning -as it has been done for the ESR1 gene in ovarian cancer [22] -must be performed for each gene individually and is therefore not in the scope of present study.…”

Vascular endothelial growth factor C mRNA expression is a prognostic factor in epithelial ovarian cancer as detected by kinetic RT-PCR in formalin-fixed paraffin-embedded tissue

“…Although we do not provide a direct comparison between VEGF-C mRNA determinations in fresh frozen and FFPE tissue, our study indicates that formalin-fixed paraffin-embedded tissue is suitable for the determination of VEGF-C gene expression using kinetic RT-PCR. The successful validation of markers identified in fresh frozen tissue after transfer into formalin fixed tissue analysis has recently been published for the prognostic role of estrogen receptor 1 mRNA expression in ovarian cancer [17,18]. To our knowledge, this is the first study to determine VEGF-C expression in epithelial ovarian cancer using kinetic RT-PCR and the first to assess VEGF-C mRNA expression in formalin-fixed paraffin-embedded tissue samples.…”