Extracellular vesicles and the regulation of tumor immunity: Current progress and future directions.

As nano-level information carriers, extracellular vesicles (EVs) contain proteins, DNA or RNA, which maintain the transmembrane transport of biomolecules and the homeostasis of normal cells. EVs can be released by most cell types and absorbed by specific recipient cells, subsequently affecting phenotypic expression. EVs are believed to play an important role in cellular communication, especially in immune cells. During tumor development, EVs of different origins have different effects on the survival and growth of tumor cells. Some tumor cell-derived EVs can mediate tumor immunosuppressive responses by inhibiting the differentiation and maturation of dendritic cells (DCs) and by negatively regulating the expression of T cell receptors, causing tumor cells to escape immune surveillance and proliferate. EVs have therefore become a key component of tumor cell proliferation and metastasis. In contrast, EVs derived from DCs mediate antitumor immune activation by inducing the killing and inhibitory effects of the immune system. This makes it an antigen component of the antitumor response. Integrating the interaction and connection of EVs to immunosuppression and immune response is significant for the application of EVs in clinical practice. Here, we reviewed the research progress on the role of EVs in the immune regulation of tumors.