Although the effects of anti-GITR mAb therapy on each immune cell type have yet to be fully elucidated, it is clear that such treatment suppresses the inhibitory T regulatory cells within the tumor microenvironment and is most likely the driver of synergism between XRT and anti-GITR mAb therapy in both mouse tumor models and potentially humans, as evidenced by the ongoing clinical trial investigating anti-GITR and anti-PD1 therapies (7). Here, TNFRSF18 is linked to neoplasm.