PD-L1 and intratumoral immune response in breast cancer




Wang, Zhi-Qiang
Milne, Katy
Derocher, Heather
Webb, John R.
Nelson, Brad H.
Watson, Peter H.

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Purpose: PD-L1 is thought to play an important role in the antitumor immune response. In this study, we investigated the expression of PD-L1 within breast tumor subsets to better define its prognostic significance. Methods: Immunohistochemistry was performed to determine PD-L1 tumor cell expression and to enumerate CD8, CD4 and CD68 tumor-infiltrating leucocytes (TIL) in a cohort of 443 breast cancers categorized by molecular subtype. Results: Across the entire cohort, PD-L1 tumor cell expression was observed in 73/443 (16.5%) cases and associated with known indicators of poor prognosis, including low patient age, high tumor grade, ER/PR negative status, but not with outcome. However, in the Triple Negative breast cancer subset PD-L1 was associated with better recurrence free survival (RFS) especially within the Basal-like subset (Hazard ratio = 0.39, 95% CI = 0.22 - 0.86, p = 0.018). Combined PD-L1/epithelial CD8 positive status was also strongly associated with better RFS and OS (Hazard ratio = 0.12, 95% CI = 0.10 - 0.71, p = 0.010 and Hazard ratio = 0.11, 95% CI = 0.11 - 0.68, p = 0.006 respectively) in the Basal-like subgroup. Conclusions: PD-L1 expression is associated with better patient survival in Basal-like breast cancer.



PD-L1, CD4, CD8, CD68, breast cancer


Wang, Z.; Milne, K.; Derocher, H.; Webb, J.R.; Nelson, B.H.; & Watson, P.H. (2017). PD-L1 and intratumoral immune response in breast cancer. Oncotarget, 8(31), 51641-51651. https://doi.org/10.18632/oncotarget.18305