CD274 and neoplasm: We also found that the number of cells expressing PD-1, a co-inhibitory checkpoint molecule and a marker of T cell exhaustion [34], was significantly decreased, whereas that of PD-L1+ cells, which were considered to be non-tumor cells based on morphology, was increased in response to Am80 in tumors developed in WT mice but not Meflin KO mice (Fig. 3e and Supplementary Fig. S8).