PD-L1 is regulated by NR4A1/Sp1 in breast cancer cells and treatment with CDIM/NR4A1 antagonists decreased PD-L1 protein levels and Fig. 1A illustrates the GC-rich PD-L1 promoter and the structure of the 1,1-bis(3’-indolyl)-1-(3,5-disubstitutedphenyl) methane (CDIM) compounds used in this study [23]. Here, SP1 is linked to breast cancer.