Engineered exosomes for breast cancer immunotherapy: Emerging strategies and translational potential

Breast cancer remains one of the leading causes of cancer-related mortality in women worldwide, despite significant advances in early detection and conventional therapies. Immunotherapy has emerged as a promising strategy to harness the body's immune system to combat tumors. However, limitations such as immune escape mechanisms and inefficient drug delivery continue to challenge its effectiveness. In recent years, engineered exosomes, cell-derived nanoscale vesicles, have gained attention as innovative carriers for cancer immunotherapy due to their natural biocompatibility, low immunogenicity, and inherent targeting capabilities. This review highlights recent advancements in the design and functionalization of exosomes for breast cancer immunotherapy, including the loading of immune-stimulating molecules, genetic cargos, and surface modifications to enhance tumor specificity. We also discuss their advantages over conventional nanocarriers, immunological mechanisms, preclinical evidence, and challenges related to clinical translation. While significant progress has been made, further research is needed to overcome current barriers and fully exploit the potential of engineered exosomes as a next-generation platform in breast cancer immunotherapy.