Prognostic potential of ERG (ETS-related gene) expression in prostatic adenocarcinoma

Abstract

Following patients after prostatectomy can be expensive and stressful, therefore, a novel and reliable approach to improve stratification is needed both at diagnosis of PCa and following its treatment. We evaluate the association of both ERG and claudin-4, claudin-5, and beta-catenin expression in tumor tissues of patients with organ-confined and advanced prostatic adenocarcinomas. A total of 30 patients were included in the study. Nine men who underwent radical prostatectomy for organ-confined (pT2N0M0) cancer (OCC), 10 patients with clinically advanced cancer (CAC), and 11 controls with benign prostatic hypertrophy (BPH). Using immunohistochemistry applied to tissue microarrays, each group was evaluated for beta-catenin, claudin-4, claudin-5, and ERG expression. The expression of ERG was higher in the CAC group when compared to OCC and BPH (p = 0.7684, p = 0.0224, respectively). Among these patients, 5 from the CAC (45 %) and 5 from the OCC group (56 %) stained positively for ERG (p = 1.0). The mean staining score for those with ERG+ advanced cancer was greater than that for the ERG+ organ-confined cancer (p = 0.0209). ERG staining correlated with Gleason score (Pearson's correlation: 0.498, p = 0.0051), but not with serum PSA level (Pearson's correlation: 0.404, p = 0.1202). When analyzing outcome data, high ERG expressing tumors have shown a significantly worse overall survival (p = 0.0084). Our results of presence or absence of claudin-4 and claudin-5 and ERG staining intensities suggest their potential as prognostic factors for prostate cancer.