PVR and neoplasm: TIGIT blockade during tumor co-culture only restored CD107a expression for PVR+-K562-restimulated NK cells; resulting in an increase in the frequency of CD107a+ NK cells compared to isotype control conditions (41% with TIGIT blockade vs. 19% with isotype control; p < 0.0001), resulting in comparable frequencies of CD107a+ NK cells to those observed for PVR−-K562-restimulated NK cells, which remained unchanged after TIGIT blockade (41% with PVR+ cell restimulation vs. 39% with PVR−).