The pathological relevance of the identified mechanism was validated by the expression of p-EGFR (Tyr 1068), p-GSK3β (Ser 9), PD-L1 and the cytotoxic T-cell activation indicator granzyme B in human breast tumour specimens using immunohistochemical (IHC) staining in which PD-L1 expression correlated positively with p-EGFR (P=0.007, Pearson χ2-test) and p-GSK3β (P=0.0001, Pearson χ2-test) but negatively with granzyme B (P=0.043, Pearson χ2-test; Supplementary Fig. 8c and Supplementary Table 1). Here, GZMB is linked to breast neoplasm.