Exosome-based liquid biopsy: A new frontier in early cancer diagnosis.

Early-stage diagnosis offers the greatest survival advantage in oncology, and yet conventional liquid-biopsy markers - circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) - depend on cell death or mechanical shedding and therefore appear late in disease progression. Exosomes, 40-160 nm lipid-bilayer vesicles secreted by viable cells, emerge earlier, outnumber CTCs by several orders of magnitude, and preserve multi-omic cargo that mirrors intratumor heterogeneity. Rapid advances in enabling technologies are driving continual breakthroughs in exosome-based liquid biopsy, laying a solid foundation for its accelerated translation into clinical practice. Key hurdles remain: standardizing exosome isolation, defining quantitative cut-offs that separate malignant from inflammatory EV surges, and building probabilistic multi-omic models to pinpoint tissue origin. Eliminating these obstacles could advance detection by months and shift care from late salvage to true early interception.