For example, Li et al identified EGF signaling induces PD-L1 glycosylation, and inhibition of EGF-mediated PD-L1 stabilization by gefitinib sensitizes PD-1 blockade therapy in breast cancer mouse model.11 Another work by Ye et al demonstrated that MMP2/9 increases the expression level of PD-L1, and reducing PD-L1 expression by MMP2/9 inhibitor SB-3CT, enhances the therapeutic efficacy of PD-1 blockade in melanoma and Lewis lung carcinoma.43 Our clinical data showed that 26.3% of patients with high eEF2K expression had a poor prognosis. This evidence concerns the gene PDCD1 and breast cancer.