title: Improving natural killer cell cancer immunotherapy.
abstract: OBJECTIVE
  Natural killer (NK) cells are innate lymphoid cells specialized to eliminate malignant cells via direct cytotoxicity and immunoregulatory cytokine production. As such, NK cells are ideal as cellular therapy for cancer patients, and several studies have provided proof of principle that adoptively transferred NK cells can induce remissions in patients with leukemia. A clear understanding of the mechanisms underlying NK cell antitumor responses, including target cell recognition, activation status, and negative regulatory signals will improve NK cellular therapy for cancer patients.
  
  
  RESULTS
  Clinical studies have demonstrated the safety and preliminary efficacy of NK cell adoptive transfer, especially in hematologic malignancies. Various NK cell sources, isolation techniques, activation approaches, and ex-vivo expansion strategies are under investigation. New approaches have been developed and are being tested to optimize NK cell therapy, including ways to better target NK cells to malignant cells, increase their functional competence, facilitate expansion in patients, and limit inhibitory signals or cells.
  
  
  CONCLUSIONS
  NK cells represent a promising cellular immunotherapy for the treatment of cancer. In addition to adoptive cellular therapy, adjunct treatments that optimize NK cell targeting and function will enhance their potency and broaden their potential use to many cancer types.
authors.affiliation: Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Berrien-Elliott
authors.forename: Rizwan
authors.initials: R
authors.lastname: Romee
authors.forename: Todd A
authors.initials: TA
authors.lastname: Fehniger
mesh_terms: D019264:Adoptive Transfer; D064987:Cell- and Tissue-Based Therapy; D018450:Disease Progression; D006801:Humans; D007167:Immunotherapy; D007694:Killer Cells, Natural / Q000276:immunology*; D009369:Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy*