A group of impressive immunotherapies for cancer treatment, including immune checkpoint-blocking antibodies,
gene therapy and immune cell adoptive cellular immunotherapy, have been established, providing new weapons to
fight cancer. Natural killer (NK) cells are a component of the first line of defense against tumors and virus
infections. Studies have shown dysfunctional NK cells in patients with cancer. Thus, restoring NK cell antitumor
functionality could be a promising therapeutic strategy. NK cells that are activated and expanded ex vivo can
supplement malfunctional NK cells in tumor patients. Therapeutic antibodies, chimeric antigen receptor (CAR), or
bispecific proteins can all retarget NK cells precisely to tumor cells. Therapeutic antibody blockade of the immune
checkpoints of NK cells has been suggested to overcome the immunosuppressive signals delivered to NK cells.
Oncolytic virotherapy provokes antitumor activity of NK cells by triggering antiviral immune responses. Herein,
we review the current immunotherapeutic approaches employed to restore NK cell antitumor functionality for the
treatment of cancer.
Keywords: Natural killer cells; immunotherapy; neoplasms