Despite current risk stratification systems using traditional clinicopathologic factors, many localized and locally advanced
prostate cancers fail radical treatment (ie, radical
prostatectomy,
radiation therapy with or without
androgen deprivation
therapy). Therefore, a pressing need exists for enhanced methods of disease stratification through novel prognostic and predictive tools that can reliably be applied in clinical practice. Exosomes are 50- to 150-nm small vesicles released by
cancer cells that reflect the genetic and nongenetic materials of parent
cancer cells.
Cancer cells can contain distinct sets of
microRNA profiles, the expression of which can change owing to stress such as
radiation therapy. These alterations or distinctions in contents allow exosomes to be used as prognostic and/or predictive
biomarkers and to monitor the treatment response. Additionally,
microRNAs have been shown to influence multiple processes in prostate
tumorigenesis, including cell proliferation, induction of apoptosis, migration, oncogene inhibition, and radioresistance. Thus, comparative exosomal
microRNA profiling at different levels could help portray
tumor aggressiveness and response to
radiation therapy. Although technical challenges persist in exosome isolation and characterization, recent improvements in
microRNA profiling have evolved toward in-depth analyses of the exosomal cargo and its functions. We have reviewed the role of exosomes and exosomal
microRNAs in biologic processes of
prostate cancer progression and
radiation therapy response, with a particular focus on the development of clinical assays for treatment personalization.