Preliminary Results of Noninvasive Detection of TMPRSS2:ERG Gene Fusion in a Cohort of Patients With Localized Prostate Cancer

Abstract

Purpose: The aim of this study was to evaluate TMPRSS2:ERG fusion rates in tissue, urine, blood, and pubic hair samples in a cohort of patients with localized prostate cancer and to correlate these findings with various clinicopathological parameters.

Materials and methods: A cohort of 40 patients undergoing radical prostatectomy for localized prostate cancer (RRP group) and 10 control patients undergoing prostate biopsy were enrolled between 2006 and 2008. Urine, pubic hair, and peripheral blood samples were obtained following prostatic massage before the needle biopsy or radical prostatectomy. Quantitative polymerase chain reaction analysis was performed on all collected samples.

Results: The patients' mean age was 62.4 (±5.5) years. We observed higher expressions of TMPRSS2:ERG fusion in tissue, urine, and blood samples from the RRP group than in samples from the control group. Overall, the fusion was present in urine samples of 23 RRP patients (57.5%). To predict high-stage cancer (>T3a), the Gleason score was the only significant factor in the logistic regression analysis (score, 10.579; p=0.001). Quantitative evaluation of the gene fusion in tissue (Pearson r=0.36, p=0.011) and urine (Pearson r=0.34, p=0.014) samples had a significant positive correlation with the preoperative prostate-specific antigen level.

Conclusions: Urine sediments collected after prostatic massage appear to be a feasible noninvasive method of detecting TMPRSS2:ERG fusion. The Gleason score is the only significant factor to predict high-stage cancer (>T3a). No correlation between TMPRSS2:ERG gene fusion status and tumor stage, Gleason grade, prostate-specific antigen level, or surgical margin status was observed.

Keywords: Prognosis; Prostate neoplasms; TMPRSS2-ERG fusion protein.