Abstract: Natural killer（NK） cells is a subset of lymphocytes that mainly participate in innate immunity， and also play a key role in the antitumor immune responses. The capability of NK cells to kill tumor cells mainly depends on the synthesis of stimulatory and inhibitory signals on the cells surface. Cell lines establishment and clinical application of NK-92 cell line provide wide application prospect for tumor immunotherapy. In past years， researchers have obtained a more deeply understand about the molecular basis for NK cell recognition cancer. Together with the application of genetic modification， NK cell-based immunotherapy will be much concerned.

Key words: NK cells, Cancer, Immunotherapy