PD-L1 expression and tumor-infiltrating lymphocytes: Revisiting the antitumor immune response potential in breast cancer.

Upon analysis of 636 primary breast carcinoma patient samples, we have found that programmed cell death ligand 1 ( PD-L1 ) mRNA expression is associated with tumor-infiltrating lymphocytes (TILs). Furthermore, PD-L1 expression and elevated TILs were associated with longer recurrence-free survival. Thus, our findings indicate that PD-L1 is prognostic in breast cancer and suggests a functional link between TILs and tumor PD-L1 upregulation.