Heterogeneity of PD-L1 expression in primary tumors and paired lymph node metastases of triple negative breast cancer

Programmed cell death ligand 1 (PD-L1) is a potential predictive biomarker of the response to antiPD-L1/anti- programmed cell death 1 (PD-1) therapy in multiple cancers, including triple negative breast cancer(TNBC).