Circulating blood miRNAs for prostate cancer risk stratification: miRroring the underlying tumor biology with liquid biopsies

Abstract

Current risk stratification methods for prostate cancer – although they have seen marked improvements over the past decades – are far from perfect. Despite the significant utility of prostate-specific antigen as a biomarker to monitor for disease recurrence, it cannot predict which tumors will recur or recommend the best treatment for patients. Similarly, although biopsies are imperative for diagnosis and staging, they are saddled with limitations and risks. We must move toward a noninvasive biomarker that has predictive and prognostic efficacy. We therefore review the current literature on circulating miRNA biomarkers, apply their use to two significant clinical problems (ie, how limitations of prostate biopsies can impact diagnosis and treatment management, and the need to tailor treatment for a clinically heterogeneous disease), and evaluate how circulating miRNAs have inherent properties that make them ideal liquid biomarkers. We also outline current gaps in knowledge that must be addressed before they can be implemented into routine clinical practice. With further research on their function and validation of their biomarker utility in large prospective cohorts, circulating miRNAs will likely prove to be the liquid biopsies of tomorrow.

Keywords:

• miRNA
• biomarker
• prostate cancer
• risk stratification
• serum
• plasma

Acknowledgments

The authors would like to thank the generous support provided by Prostate Cancer Canada, Movember Foundation (Movember Rising Star award recipient, Grants # RS2014-03, #D2013-24), Telus Motorcycle Ride For Dad (Huronia Branch), and a Ministry of Research and Innovation Early Researcher Award. CH was supported by the Strategic Training in Transdisciplinary Radiation Science for the 21st Century (STARS21) training program funded by the Terry Fox Foundation; Princess Margaret Cancer Centre; the Government of Ontario; and Lawrence, Ila, and William Gifford Scholarship in Radiation Oncology and Surgery at the University of Toronto. CH was also a recipient of the Queen Elizabeth II Graduate Scholarship in Science and Technology (QEII-GSST) funded by Sunnybrook Health Sciences Centre, University of Toronto, and the Government of Ontario.

Disclosure

The authors report no conflicts of interest in this work.