Noninvasive Detection of TMPRSS2:ERG Fusion Transcripts in the Urine of Men with Prostate Cancer 1

We recently reported the identification of recurrent gene fusions in the majority of prostate cancers involving the 5V untranslated region of the androgenregulated gene TMPRSS2, the ETS family members ERG, ETV1, ETV4. Here we report the noninvasive detection of these gene fusions in the urine of patients with clinically localized prostate cancer. By quantitative polymerase chain reaction, we assessed the expression of ERG, TMPRSS2:ERG transcripts in urine samples obtained after prostatic massage from 19 patients (11 prebiopsy, 8 pre-radical prostatectomy) with prostate cancer. We observed a strong concordance between ERG overexpression, TMPRSS2:ERG expression, with 8 of 19 (42%) patients having detectable TMPRSS2:ERG transcripts in their urine. Importantly, by fluorescence in situ hybridization, we confirmed the presence or the absence of TMPRSS2:ERG gene fusions in matched prostate cancer tissue samples from three of three patients with fusion transcripts in their urine, from two of two patients without fusion transcripts in their urine. These results demonstrate that TMPRSS2:ERG gene fusions can be detected in the urine of patients with prostate cancer, support larger studies on prospective cohorts for noninvasive detection of prostate cancer.