CAR-expressing NK cells for cancer therapy: a new hope.

Since the approval in 2017 and the amazing achievement of Kymriah and Yescarta, the number of basic researchers and clinical trials investigating the safety and efficacy of chimeric antigen receptor-expressing T cells (CAR-T cells) has been relentlessly increasing. Up to now, more than 200 clinical trials are listed on clinical trial database of NIH and the basic research is countless. However, the production of allogeneic CAR-T cells products is still expensive and has toxicity. Thus, more effort is needed to develop reliable off-the-shelf cellular therapeutic methods with safety and efficiency for the treatment of patients with cancer. As a kind of innate effector lymphocyte with potent antitumor activity, natural killer cells (NK cells) have attracted much attention. Until now, basic and clinical research has shown that chimeric antigen receptor-expressing NK cell (CAR-NK) therapy may play a significant anti-tumor role and its safety is higher than CAR-T cell therapy. In this review, we discuss advantages and shortages of employing CAR-NK cells as a novel cellular therapy against cancer.