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European urology

A panel of TMPRSS2:ERG fusion transcript markers for urine-based prostate cancer detection with high specificity and sensitivity.


PMID 21144642

Abstract

The TMPRSS2:ERG fusion is both prevalent and unique to prostate cancer (PCa) and has great potential for noninvasive diagnosis of PCa in bodily fluids. To evaluate the specificity and sensitivity of the TMPRSS2:ERG fusion in urine from diverse clinical contexts and to explore potential clinical applications. A total of 101 subjects were enrolled in 2008 from urologic oncology clinics to form three study groups: 44 PCa free, 46 confirmed PCa, and 11 negative prostate biopsies. The PCa-free group included females, healthy young men, and post-radical prostatectomy (RP) patients. The confirmed PCa group was composed of patients under active surveillance, scheduled for treatment, or with metastatic disease. Urine was collected after attentive digital rectal exam (DRE) and coded to blind group allocation for laboratory test. RNA from urine sediments was analyzed using a panel of four TMPRSS2:ERG fusion markers with quantitative polymerase chain reaction (qPCR). Our fusion markers demonstrated very high technical specificity and sensitivity for detecting a single fusion-positive cancer cell (VCaP) in the presence of at least 3000 cells in urine sediments. In clinical analysis, there were no fusion-positive samples in the PCa-free group (0 of 44 samples), while there were 16 of 46 (34.8%) fusion-positive samples in the confirmed PCa group. The fusion incidence varied significantly among the three PCa subgroups. The clinical sensitivity increased to 45.4% in cancer patients prior to treatments. The fusion markers were detected in 2 of 11 (18.2%) biopsy-negative patients, suggesting potentially false negative biopsies. This study is not prospective and is limited in sample sizes. Our novel panel of TMPRSS2:ERG fusion markers provided a very specific and sensitive tool for urine-based detection of PCa. Theses markers can potentially be used to diagnose patients with PCa who have negative biopsies.