Tumor co-culture in the presence of isotype control antibodies decreased the frequency of CD107a+ NK cells upon restimulation with K562 cells (37 ± 5% for PVR− (p = 0.004) and 19 ± 8% PVR+ (p < 0.0001)) with a larger decrease with PVR+-K562 cells compared to PVR− cells (p = 0.005). This evidence concerns the gene PVR and neoplasm.