Natural Killer Cell-Based Cancer Immunotherapy: From Bench to Bedside

Natural killer (NK) cells are innate cytotoxic lymphocytes involved in the surveillance and elimination of cancer. The increasing number of studies have identified novel methods for enhancing the anti-tumor immunity of NK cells and expanding NK cells ex vivo, which paved the way for a new generation of anticancer immunotherapies. In this chapter, we will review the following aspects regarding NK cells, including the inhibitory and activating receptors modulating NK cell activity, NK cell development, the cytotoxic mechanism of NK cells, isolation, expansion and characterization of NK cells, and the source for NK cells. Moreover, we will highlight the cutting-edge immunotherapeutic strategies in preclinical and clinical development such as chimeric antigen receptor (CAR)-NK cells, as well as the adoptive NK transfer to target cancer stem cells (CSCs). Last, we will discuss the challenges NK cells face which should be overcome to achieve cancer clearance.