PRF1 and malignant colon neoplasm: Anti-hPVRIG mAb significantly enhanced the expression of effector molecules (NKG2D, CD107a and perforin) of NKG cells in co-culture with SW620 colon cancer cells (Fig. 7b) and improved their cytotoxicity against SW620 cells at effector/target ratios of 1:1 and 5:1 in vitro (Fig. 7c).