Exosomes-based biomarker discovery for diagnosis and prognosis of prostate cancer

African American men in the United States have higher incidence and mortality rates due to prostate cancer (PCa) compared to other races. In 2016 alone, nearly 30,000 cases of PCa in African American men were diagnosed and 4,450 men died from PCa. The underlying reasons for this health disparity in PCa are complex and include social, economic, and biologic determinants. To reduce or eliminate this health disparity, we must better understand the biology of the disease in African Americans and then develop novel diagnostic and prognostic biomarkers useful for timely and effective treatment decisions. Recently, there has been remarkable progress in understanding the role of exosomes (vesicles of 30-150 nm diameter) in cancer development and progression. Exosomes are loaded with unique cargo, including proteins, nucleic acids, lipids, and metabolites, that could predict the cells of their origin. Therefore, circulating exosomes in cancer patients are being used as a type of biopsy to identify novel biomarkers for early diagnosis, prognosis, and therapeutics. In this review, we discuss the promising use of exosomes to (a) identify race-related unique biological features of PCa, and (b) discover novel biomarkers for better diagnosis and prognosis of PCa, with the goal of reducing cancer health disparities.