CD274 and breast cancer: For that, GFP-expressing 4K5 cells (derived from a BC tumor developed in a DKO mouse injected with adenoviruses expressing Cre-recombinase under the control of keratin 5 promoter) were subcutaneously injected in the flank of syngeneic mice and treated with CM-1758 and/or PD-L1 blockade (Fig. 4a).