IFNG and cancer: The activation of the IFN-γ/STAT1 axis is then responsible for the increase in PD-L1 and in parallel the decrease in TRAIL-R2.166,167 Blockade of the IFN-γ receptor in this same resistant model leads to the increase in TRAIL-R2 and allows natural killer (NK) cells to stimulate extrinsic apoptosis in the cancer cells.