Exosome-based cancer vaccine: a cell-free approach

Despite advancements in medical research, cancer remains a significant and persistent cause of death globally. Cancer vaccine, a novel approach, holds immense promise in development of potentially effective cancer treatment. While the concept of developing cancer vaccines has been explored for decades, significant challenges have hindered their clinical translation. Recent researchers have introduced exosomes as the key element for novel cell-free approach of cancer vaccines. Exosomes are a type of extracellular vesicle (EVs) secreted by various cells. These tiny structures can transport and deliver important biomolecules, such as DNA, RNA, proteins, lipids, and immune-stimulatory molecules, to stimulate the body's anti-tumor immune response. Their biocompatibility, targeting ability, immunogenicity, and a notable capacity to cross biological barriers nominate them as promising candidates for cancer vaccine development by addressing current challenges in cancer therapy. This review explores the current state of knowledge on the efficacy of exosomes from various sources for personalized cancer vaccine development, preclinical and clinical evaluations, along with the strategies to optimize immunogenicity and antigen presentation. We also discuss the challenges and potential solutions for overcoming tumor microenvironment-related hurdles, highlighting the promise of exosome-based approaches for cancer immunotherapy by developing a novel cell-free cancer vaccine in future.