Estrogen receptor alpha and beta expression in a case matched series of serous and endometrioid adenocarcinomas of the ovary.

Objective: The purpose of this study was to analyze estrogen receptor alpha and beta (ERalpha, ERbeta) expression in a stage and grade matched cohort of patients with serous and endometrioid adenocarcinoma of the ovary.

Methods: Forty-two patients from 1991 to the present were found to have the diagnosis of endometrioid adenocarcinoma of the ovary and have tissue available for analysis. Of these 42, ten were selected for analysis. These were stage and grade matched with ten patients having serous adenocarcinoma of the ovary during the same time period. ERalpha and ERbeta mRNA was detected by a multiplex RT-PCR and amplification of random hexamer generated cDNA using a housekeeping gene (G3PD) as a control for mRNA quality and quantity. Methylation specific PCR (MS-PCR) was used to correlate methylation of the ERalpha and ERbeta CpG islands with mRNA expression status.

Results: ERalpha expression was present in ten of ten endometrioid adenocarcinomas but in only five of ten serous carcinomas (chi2, p = 0.01). ERbeta expression was present in six of ten endometrioid adenocarcinomas and in four of ten serous caricinomas (chi2, p = 0.65). Methylation of the ERalpha and ERbeta CpG islands was found in tumors without mRNA expression but not in the tumors with mRNA expression (p = 0.005).

Conclusions: ERalpha expression, but not ERbeta expression, is significantly more common in endometrioid than serous adenocarcinomas of the ovary when controlled for stage and grade. The role of methylation in ER silencing may lead to potential therapeutic interventions.