CD226 and neoplasm: The expression of activatory receptors NKp46, DNAM-1 and CD57 was decreased on NK cells in primary tumour compared to blood (NKp46: 9.8% on primary tumour NK cells vs 18.2% on peripheral NK cells, p=0.0020; DNAM-1: 59.7% vs 71.7%, P<0.0001; CD57: 38.9% vs 59.6%, p<0.0001).