Introduction: Recent studies show a potential benefit of therapies that target programmed death receptor 1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) inhibitory checkpoints in a subgroup of patients with non-small-cell lung cancer (NSCLC), without the clinicopathologic characteristics related to positive responses to these treatments being well determined. The aim of this study was to determine PD-1, PD-L1, and CTLA-4 gene expression at the mRNA level in tumoral tissue from patients with NSCLC and analyze their possible relationship with the clinicopathological characteristics and their potential prognostic role.
Patients and methods: PD-1, PD-L1, and CTLA-4 expression levels were analyzed using real-time quantitative reverse transcriptase polymerase chain reaction in fresh-frozen tumor and normal adjacent lung tissue samples from 78 patients with NSCLC. Later, a significant association between mRNA levels, clinicopathologic characteristics, and patient's survival was assessed.
Results: No significant correlation between gene expression levels and sex, age, histological type, smoking status, pathologic stage, or tumor differentiation was found. However, higher levels of PD-1 were significantly associated with worse prognosis in patients with NSCLC, and PD-L1 overexpression was associated with a worse prognosis in stage I patients and in Grade 1 to 2 tumors.
Conclusion: Alterations in PD-1/PD-L1 and CTLA-4 expression in lung tumoral tissue seem not to be related to age, sex, smoking status, histological type, pathological stage, or tumor differentiation degree. However, PD-1 and PD-L1 overexpression might predict worse survival in patients with stage I NSCLC and in well differentiated tumors.
Keywords: Clinicopathology; Immunotherapy; Inhibitory checkpoints; Predictive markers; Prognosis.
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