Bacterial outer membrane vesicles (OMVs), naturally released by Gram-negative bacteria, are a type of lipid bilayer nanoparticles containing many components found within the parent bacterium. Despite OMVs were first considered mere by-products of bacterial growth, recent studies have shown them as a highly adaptable platform for tumor vaccine. Here, we first demonstrate the biogenesis of OMVs, then review the strong immunogenicity of OMVs as an immune adjuvant in tumor vaccine and its excellent vaccine delivery capability, and finally discuss OMVs' engineering potentials through summarizing recent scientific advancements in genetic engineering, chemical modification, and nanotechnology. We also point out the clinical trials and future challenges of OMV-based vaccine. Overall, this review offers valuable insights into cancer immunotherapy, providing a roadmap for leveraging OMVs as a versatile platform for next-generation cancer vaccines.
