The role of miRNA in diagnostics

Whilst the promise of RNA interference (RNAi) continues to expand in the therapeutic environment, the utility of the endogenous RNAi mechanism, microRNAs (miRNA), in diagnostics has been proven with the successful commercialization of a biopsy assay for the identification of cancer of unknown primary origin (CUP). The implications and consequences in personalized medicine arising from this highly sensitive and specific approach are substantial, however, the true potential is only beginning to be understood, as reports of disease-specific miRNA signatures in circulating lymphocytes, blood plasma/ serum, lung sputum, saliva and urine have been described, even in diseases where no diagnostic tools exist. This review summarizes the various approaches in miRNA biomarker discovery in addition to key findings in the field with the highest potential for clinical development