Novel insights in CAR-NK cells beyond CAR-T cell technology; promising advantages

CAR-T (chimeric antigen receptor T cell) technology, which has recently showed successful results in the treatment of hematological tumors, has been the focus of attention as one of the most potent approaches in tumor immunotherapy. However, side effects and limitations of this application, such as the risk of graft versus host disease (GvHD), make it challenging to be as accessible as other treatments. Natural killer cells (NK) could be transplanted without alloreactivity, making them as an off-the-shelf product. CAR-NK (chimeric antigen receptor NK cell) therapy can circumvent some serious limitations of CAR-T cell therapy. Application of CAR-NK cells have some considerable advantages over CAR-T cells. These include lack of cytokine release syndrome (CRS), neurotoxicity, and GvHD when using allogenic CAR-T cell. These features lessen the risk of tumor antigen loss and disease relapse. Moreover, NK cells which were derived from different sources, can make the CAR therapy more feasible. In this narrative review, we outlined the key features of CAR-NK cells as an alternative to CAR-T cell therapy in cancer immunotherapy and highlighted the main advantages.