Urine biomarkers in prostate cancer.

The deficiencies of serum PSA as a prostate-cancer-specific diagnostic test are well recognized. Thus, the development of novel biomarkers for prostate cancer detection remains an important and exciting challenge. Noninvasive urine-based tests are particularly attractive candidates for large-scale screening protocols, and biomarker discovery programs using urine samples have emerged for detecting and predicting aggressiveness of prostate cancer. Some new biomarkers already outperform serum PSA in the diagnosis of this disease. Currently, the PCA3 (prostate cancer antigen 3) urine test is probably the best adjunct to serum PSA for predicting biopsy outcome, and has proven its clinical relevance by surpassing the predictive abilities of traditional serum biomarkers. New research methods are also emerging, and high-throughput technologies will facilitate high-dimensional biomarker discovery. Future approaches will probably integrate proteomic, transcriptomic and multiplex approaches to detect novel biomarkers, and aim to identify combinations of multiple biomarkers to optimize the detection of prostate cancer. In addition, an unmet need remains for markers that differentiate indolent from aggressive cancers, to better inform treatment decisions.