Introduction: Prostate cancer (PCa) is one of the most common malignancies in men and a major cause of cancer deaths among men worldwide. Prostate specific antigen (PSA) monitoring and histopathological examination of tumor biopsies remain gold standards in PCa diagnostics. These clinical parameters are not well suited for patient stratification, predicting and monitoring treatment response. On the other hand, liquid biopsies offer a unique opportunity to easily isolate tumor-derived material for longitudinal clinical assessment. Areas covered: In this review we focus on the clinical application of novel liquid biomarkers that have the potential to monitor and stratify patients in order to achieve better therapeutic effects and improve clinical outcomes. Enumeration and characterization of circulating tumor cells (CTCs), tumor-educated platelets, exosomes, and cell-free nucleic acids have been studied for their clinical utility in PCa diagnostics, prognostics, monitoring treatment response and guiding treatment choice. Expert opinion: Liquid biomarkers have high potential to be used for prognosis, monitoring treatment response and guiding treatment selection. Although there is a remarkable progress in PCa biomarker discovery, their clinical validation is very limited. Research should be focused on biomarker validation and the incorporation of these biomarkers in clinical practice.

Expert review of molecular diagnostics. 2019 Oct 11 [Epub ahead of print]

Emmy Boerrigter, Levi N Groen, Nielka P Van Erp, Gerald W Verhaegh, Jack A Schalken

Department of Pharmacy, Radboud Institute for Health Sciences, Radboud university medical center , Nijmegen , The Netherlands., Department of Experimental Urology, Radboud Institute for Molecular Life Sciences, Radboud university medical center , Nijmegen , The Netherlands.