TSPO and neoplasm: Here, we show that similar to PD-L1 [10, 11, 18], TSPO also protects tumor cells against an attack by tumor specific cytotoxic T cells, albeit through a different, complementary mechanism: PD-L1 suppresses the activation and function of a T cell [37], while TSPO reduces the sensitivity of GB towards cytotoxic agents released by the T cell.