CD226 and neoplasm: However, the expression of the tumour‐sensing NK cell‐activating receptors NKp30, NKG2D and DNAX accessory molecule‐1 (DNAM‐1) and the surface molecules tetherin/CD317 and CD2 were all significantly reduced on the GBM tumour‐derived NK cells compared to those from matched peripheral blood (Fig. 2b).