CD274 and neoplasm: In order to compare the biological anti-tumor activity of PD-L1_1 with that of the clinically validated anti-PD-L1 mAb Atezolizumab, we tested them in parallel at the dose of 100 nM on the indicated breast cancer cells (Fig. 3 and Supplementary Fig. S1), by including an unrelated IgG4 isotype antibody as a negative control.