Expression patterns of programmed death ligand 1 correlate with different microenvironments and patient prognosis in hepatocellular carcinoma
Menée à partir de l'analyse d'échantillons tumoraux prélevés sur 453 patients atteints d'un carcinome hépatocellulaire, cette étude met en évidence une corrélation entre des profils d'expression de PD-L1, différents micro-environnements tumoraux et la survie globale des patients
Background : Recent clinical studies have suggested that programmed death ligand 1 (PD-L1) expression in a tumour could be a potential biomarker for PD-L1/PD-1 blockade therapies.
Methods : To better characterise PD-L1 expression in hepatocellular carcinoma (HCC), we analysed its expression patterns in 453 HCC patients by double staining for CD68 and PD-L1 using the Tyramide Signal Amplification Systems combined with immunohistochemistry. We also investigated its correlation with clinical features, prognosis and immune status.
Results : The results showed that PD-L1 expression on tumour cells (TCs) was negatively associated with patients’ overall survival (OS; P = 0.001) and relapse-free survival (RFS; P = 0.006); however, PD-L1 expression on macrophages (M
φs) was positively correlated with OS (P
= 0.017). Multivariate analysis revealed that PD-L1 expression on TCs and M
φs were both independent prognostic factors for OS (hazard ratio (HR)
= 1.168, P = 0.004 for TC-PD-L1; HR = 0.708, P = 0.003 for M
φ-PD-L1). Further studies showed that Mφ-PD-L1+ tumours exhibited an activated immune microenvironment, with high levels of CD8+ T-cell infiltration and immune-related gene expression.
Conclusion
:
Our study provided a novel methodology to evaluate PD-L1 expression in the tumour microenvironment, which might help to select patients who would benefit from anti-PD-1/PD-L1 immunotherapies.
British Journal of Cancer , résumé, 2018