Are extracellular vesicles ready for the clinical laboratory?

The diagnostic potential of exosomes and extracellular vesicles (EVs) for liquid biopsies was first demonstrated over a decade ago, but despite a lot of progress in the scientific field there are still very few applications of EVs that are ready for implementation in clinical laboratories for routine diagnostic use. Despite good options for routine isolation of EVs and a wide analyte target space for assay development (incl. RNA, DNA, proteins and intact EVs) assessable by standard detection technologies, the attrition rate in translating biomarker reports in the academic literature to clinical assays is very high. While there are examples of successful development, the largest obstacle to increased clinical utilization is the lack of good biomarkers that can withstand rigid clinical validation, and which make use of the EVs’ unique capabilities as a biomarker platform.

There is a significant attrition on the path from academic research through translation into clinically validated assays. Excluding studies labelled as withdrawn, terminated, not yet recruiting, suspended or unknown status (94 entries), and the number of clinical assays (4 tests) and commercially available assays (1 test) was determined through manual review and curation of literature search results.