Exosome-based vaccines in cancer immunotherapy: antitumor mechanisms, engineering strategies, and challenges

Exosome-based vaccines hold significant promise in cancer immunotherapy, yet their native forms face inherent challenges, including imprecise targeting, suboptimal immunogenicity, and poor controllability of antigen loading. This review posits that engineering is pivotal to transforming exosomes from passive carriers into active, programmable therapeutic platforms. We systematically dissect the multifaceted antitumor mechanisms of exosomes and critically evaluate how various engineering strategies (e.g., physical loading, genetic modification, membrane functionalization) are designed to address these specific biological bottlenecks, thereby establishing a coherent "biological limitation-engineering solution" framework. Building on this foundation, we assess their application potential and ongoing challenges in areas such as personalized neoantigen vaccines.