Clinical relevance of extracellular vesicles in cancer - therapeutic and diagnostic potential.

Extracellular vesicles (EVs) encompass a multitude of lipid bilayer-delimited particles, of which exosomes are the most widely studied. Bidirectional cell-cell communications via EVs have a pivotal role in the physiology of multicellular organisms. EVs carry biological cargoes (including proteins, RNA, DNA, lipids and metabolites) capable of mediating a range of pleiotropic cellular functions. Over the past decade, EVs released by cancer cells (onco-EVs) have been shown to promote cancer progression including tumour outgrowth and metastatic dissemination. Furthermore, the innate ability of EVs to protect vulnerable molecular cargoes (such as RNA, DNA or proteins) from enzymatic degradation, their presence in most biofluids and the ability to transverse biological barriers to reach distant organs make them ideal targeted drug delivery systems, including in patients with cancer. Many of these properties also support investigations of EVs as biomarkers with potential roles in both diagnosis and treatment monitoring. In this Review, we describe advances in the development of EVs as cancer therapeutics or biomarkers, including cancer vaccines, targeted drug delivery systems and immunotherapies, as well as potential roles in early cancer detection, diagnosis and clinical management. We also describe the potential of emerging technologies to support further discoveries as well as the clinical translation of EVs into diagnostic and therapeutic clinical tools. We highlight the potential of single-EV and onco-EV detection and discuss how advances in multi-omic and artificial intelligence-enabled integration are providing new biological insights and driving clinical translation.