CD226 and neoplasm: Interestingly, our observations also emphasize that the NK cell receptors involved in NK cell antitumor immunity differ according to the tumor type: in breast cancer the main receptors involved in NK cell cytotoxicity are DNAM-1 and NKG2D [29] ; whereas in melanoma NKp30, NKp44 and NKG2D are the receptors that trigger NK cell functions [24].