Exosomes as Pivotal Mediators of Tumor-Immune Communication: Implications for Immunotherapy and Liquid Biopsy

Exosomes are membrane-bound vesicles secreted by almost all types of cells, including but not limited to immune cells, neurons, epithelial cells, and cancer cells. Exosomes carry DNA, RNA, lipids, metabolites, as well as cytoplasmic and cell surface proteins. Their role in cancer progression is dynamic and is related to the type of cancer, genetics, and stage. At the same time, exosomes have attracted widespread attention as key mediators of intercellular communication in the tumor immune microenvironment (TME). This comprehensive review delineates the pleiotropic roles of exosomes in tumor immunobiology, emphasizing their bimodal capacity to either foster immunosuppression or potentiate antitumor immunity. We systematically synthesize recent advancements in exosome-based immunotherapeutic regimens, with particular emphasis on their synergistic efficacy when integrated with established modalities, namely immune checkpoint blockade and adoptive cellular therapy. Furthermore, we critically appraise emergent technologies for exosome isolation and characterization, underscoring their transformative implications for liquid biopsy platforms in real-time immune surveillance and the development of predictive biomarkers. This review posits exosome-centric strategies as a paradigm-shifting frontier in precision immuno-oncology, furnishing innovative remedies for recalcitrant therapeutic hurdles and propelling the advancement of personalized oncology care.