Bacterial Extracellular Vesicles in Oncology: Molecular Mechanisms and Future Clinical Applications

Bacterial extracellular vesicles (BEVs) have emerged as pivotal mediators of host-microbe interactions, profoundly influencing cancer biology. These nanoscale vesicles, produced by both Gram-positive and Gram-negative bacteria, carry diverse biomolecular cargo such as proteins, lipids, nucleic acids, and metabolites. BEVs play dualistic roles in tumor promotion and suppression by modulating the tumor microenvironment, immune responses, and genetic regulation. This review synthesizes the current understanding of BEVs in various cancers, including gastrointestinal, ovarian, breast, lung, brain, and renal malignancies. BEVs are highlighted for their potential as diagnostic biomarkers, prognostic indicators, and therapeutic agents, including their applications in immunotherapy and advanced engineering for precision medicine. Challenges such as heterogeneity, standardization, and clinical scalability are critically analyzed, with case examples providing actionable insights. Future directions emphasize interdisciplinary collaborations, emerging technologies, and the integration of BEV-based tools into clinical workflows. This review underscores the transformative potential of BEVs in advancing cancer diagnostics and therapeutics, paving the way for innovations in precision oncology.