Background and Objective: Exosomes are extracellular vesicles that regulate communication between cells and participate in various physiological and pathological processes. These nanovesicles transport proteins, lipids, and nucleic acids, including microRNAs (miRNAs). miRNAs are small non-coding RNA molecules that regulate gene expression. Exosomal miRNAs (exo-miRNAs) modulate many pathways involved in tumor progression, growth, metastasis, and angiogenesis. Therefore, in this review we investigated the role of exosomal miRNAs in both solid and hematological tumors, with the purpose of highlighting their potential role as disease biomarkers. Methods: Published peer-reviewed papers used as references for this narrative review were selected from the PubMed database using “exosomes”, “microRNA” and “cancers” as keywords. The time frame adopted in the bibliographic research covers an 11-year period, from January 2012 to January 2023. Key Content and Findings: This review explores the role of exosomal miRNAs as disease biomarkers. An excursus on exosomes and miRNAs is initially made to then illustrate the mechanisms of miRNAs sorting in exosomes. Exo-miRNAs can communicate with cells and can modulate their actions. Their half-life is extended thanks to the protection provided by exosomes. The role of exosomal miRNAs in different types of solid and hematological tumors is summarized highlighting the potential of disease staging and progression. Conclusions: All manuscripts studied suggest that exosomal miRNAs can be used as diagnostic and prognostic biomarkers iwn cancer. The lack of appropriate and usable biomarkers for cancer diagnosis and prognosis makes exosomal miRNAs good candidates to provide non-invasive information to guide disease management in different types of cancer.
exosomes; microRNAs; exosomal miRNAs; cancer; biomarkers