CD274 and breast cancer: When this manuscript was under preparation, we found a study demonstrated that another histone demethylase lysine-specific demethylase 1 (LSD1) may suppress the expression of PD-L1 in breast cancer cells, and inhibition of LSD1 elicits anticancer immunity in breast cancer.28 In addition, combination of LSD1 inhibitor and PD-L1 antibody showed a more profound effect in the inhibition of tumour growth.