Background
Cancer-associated fibroblasts (CAFs) are some of the most abundant components of the tumour microenvironment. A recent study suggested that in some cancers, CAFs express programmed death ligand 1 (PD-L1), which can act as a prognostic marker. The
Conclusions
CAF PD-L1 expression is a novel marker for a better prognosis of patients with TNBC, and the 73-10 assay may be suitable for immunostaining CAF PD-L1.
Methods
Immunohistochemical staining (primary antibodies of 73-10, SP142, and E1L3N) and tissue microarrays were used to analyse the expression profiles of PD-L1 in CAF in 61 patients with TNBC who underwent surgery. Overall survival (OS) was compared based on CAF PD-L1 expression, and the risk factors for OS were analysed. The relationship between clinicopathological parameters and survival was also examined.
Results
Thirty-four (55.7%) patients were positive for CAF PD-L1 (73-10) expression. Compared with CAF PD-L1 negativity, there was a significant correlation between CAF PD-L1 positivity and better OS (p = 0.029). CAF PD-L1 expression, evaluated using SP-142 or E1L3N, did not correlate with OS. CAF PD-L1-positivity (73-10) correlated significantly with better prognosis in multivariate analyses (hazard ratio: 0.198; 95% confidence interval: 0.044-0.891; p = 0.035). Conclusions: CAF PD-L1 expression is a novel marker for a better prognosis of patients with TNBC, and the 73-10 assay may be suitable for immunostaining CAF PD-L1.