It may be due to the loss of its depleting activity against TIGIT-expressing intratumoral Treg cells, which has been considered as a potential mechanism of anti-TIGIT mAb-mediated anti-tumor effect [74]; however, it is still not clear whether the anti-tumor efficacy of anti-TIGIT mAbs depends on Treg depletion, since there are recent reports that anti-TIGIT mAbs on mIgG2a isotype induce anti-tumor responses without evidence of Treg depletion in mouse tumor models [36,73]. The gene discussed is TIGIT; the disease is neoplasm.