Prognostic value of E‑26 transformation‑specific‑related gene in prostate cancer based on immunohistochemistry analysis

E-26 transformation-specific-related gene (ERG) has been implicated in prostate cancer; however, its prognostic role remains unclear. Therefore, the present study aimed to investigate the association of ERG with the prognosis after radical prostatectomy in patients with prostate cancer. Patient data were collected at the Huadong Hospital, affiliated with Fudan University, between January 2016 and March 2020. ERG protein expression was detected using immunohistochemistry. Independent-sample t-tests and χ(2) tests were used to evaluate prostate cancer prognosis depending on ERG levels. The Kaplan-Meier method was used to estimate biochemical failure-free survival (BFFS) and the log-rank test was used to test the distribution. Prognostic factors were determined using Cox regression analysis. The median patient age was 69 years (range, 47–82 years). The median prostate-specific antigen (PSA) and free-PSA levels before treatment were 9.58 ng/ml (range, 0.003-187.400 ng/ml) and 1.13 ng/ml (range, 0.0059-30.6100 ng/ml), respectively. ERG protein expression was positive in 43 (16.6%) and negative in 216 (83.4%) cases. The median follow-up period and BFFS were 30 and 28 months, respectively. There was a significant difference in biochemical recurrence (P=0.017) between patients with positive and negative ERG expression. Patients with positive ERG expression had significantly worse BFFS curves compared with those with negative ERG expression (P=0.0038). In the multivariate Cox regression analysis, positive ERG expression was found to be an independent prognostic factor in patients with prostate cancer who underwent radical prostatectomy (hazard ratio, 4.08; 95% confidence interval, 2.03-8.17; P=0.000074). In conclusion, positive ERG expression is an independent prognostic risk factor for prostate cancer. These findings may be valuable for improvements in the clinical application of ERG immunohistochemistry.