A promising frontier of circulating messenger RNA in liquid biopsy: From mechanisms to clinical applications

Liquid biopsy can revolutionize cancer patient management as repeated sampling allows real-time monitoring of disease progression and response to treatment. The circulating transcriptome represents a rich source of potential cancer biomarkers, including coding and non-coding RNAs. As techniques that have enabled us to analyze transcriptome profiling become ever more sophisticated, the great potential of extracellular messenger RNA (mRNA) and intracellular (cellular level) mRNA in liquid biopsy has gradually been realized. In this review, we aim to conclude the mRNA-based liquid biopsy in the tumorous context by illustrating the origins of mRNA markers and scientific findings, and summarizing the advantages of mRNAs over DNA-based liquid biopsy. Besides, we give a glimpse of the application of this strategy in clinical studies and analyze the gap between the bench and bedside. We speculate that mRNAs are a promising frontier of liquid biopsy.