Programmed cell death 1 (PD-1) receptor and programmed death ligand 1 (PD-L1) gene expression in primary breast cancer.

PD-1 expression is higher in breast cancers with aggressive features such as TNBC. Low PD-L1 expression may be an adverse prognostic factor. PD-1 and PD-L1 gene expression correlates with the expression of immune-related and DNA damage repair genes.