Review of research pertaining to the effect of tumor-derived exosomes on natural killer cells.

Tumor-derived exosomes (TDEs) play critical roles in many aspects of cancer progression. There have been several advances in cancer immunotherapy in recent years. A major challenge, however, has been addressed to the role of TDEs in tumor cell immune escape through their influence on the antitumor immunity of natural killer (NK) cells, a key type of immune cell. In this review, we present our overview of the effects of different TDEs on NK cell activation and NK cell toxicity. Studies on mechanism suggest that TDEs mainly affect the immune response of NK cells by inhibiting activated receptors on the surface of NK cells and downregulating the NK recognition ligand MICA/B on the tumor cell surface. In addition, a summary was documented on how to restore the cytotoxicity of NK cells and improve the drug's ability to recognize tumor cells, and a detailed explanation was also provided on the mechanism of action of the drug.