By a degranulation assay performed against the FcγR+ P815 cell line, we could prove that PD-1+ tr-NK cells responded to mAb-mediated CD16 triggering and that the simultaneous triggering of PD-1 decreased CD16-induced stimulation (Figure 5B), thus suggesting that tumor-associated PD-1+ tr-NK cells expressed a functional PD-1 inhibitory receptor. The gene discussed is FCGR2A; the disease is neoplasm.