Dendritic Cell‐Derived Extracellular Vesicles as Therapeutic Cancer Vaccines: Mechanisms and Optimization Strategies

Extracellular vesicles (EVs) are ubiquitously secreted nanoparticles that modulate the activities of recipient cells either through the transfer of bioactive cargo or by surface receptor‐mediated signalling. EVs derived from dendritic cells are increasingly recognised as promising platforms for therapeutic cancer vaccines, owing to their immunostimulatory cargo, their capacity to transfer preformed peptide–major histocompatibility complexes to antigen‐presenting cells, and their ability, in some cases, to directly activate cognate T cells. Despite encouraging preclinical results, EV‐based cancer vaccines have demonstrated limited clinical efficacy, constrained by suboptimal immunogenicity, poor lymphoid targeting, and suppression within the tumour microenvironment. Several strategies—including prioritising tumour‐specific neoantigens, co‐administering adjuvants and immunotherapies, optimising EV production and delivery protocols, and engineering EVs with tailored characteristics—aim to overcome these limitations and improve clinical outcomes.