CD274 and melanoma: It has been reported that tumor intrinsic PD1 can interact with PD-L1 and enhance proliferation of melanoma cells by activating the mTOR pathway.32 To test whether the interaction between PD-L1 and PD1 might affect TNBC cell growth, we treated MDA-MB-231 and BT549 cells with increasing concentrations of anti-PD-L1 antibody that blocked the interaction between PD-L1 and PD1, and monitored cell growth.