Circulating PD-L1 in NSCLC patients and the correlation between the level of PD-L1 expression and the clinical characteristics

BACKGROUND: The programmed cell death-1/programmed cell death-1 ligand (PD-1/PD-L1) pathway plays a crucial role in tumor evasion. This study evaluated the association between circulating PD-L1 expression and clinical characteristics in patients with advanced non-small cell lung cancer (NSCLC). METHODS: A total of 109 advanced NSCLC and 65 healthy patients from the Beijng Cancer Hospital were enrolled in the study. Circulating PD-L1 expression was tested by enzyme-linked immunosorbent assay. The associations between the level of PD-L1 expression and clinicopathologic features and prognosis were statistically analyzed. RESULTS: The expression of PD-L1 in advanced NSCLC patients was significantly upregulated compared with the healthy control (P < 0.001). The expression of PD-L1 was significantly correlated with abdominal organ metastasis (P = 0.004). A high PD-L1 expression had a worse prognosis than a low expression in patients (18.7 vs. 26.8 month, P < 0.001). CONCLUSIONS: PD-L1 was elevated in advanced NSCLC patients and may play an important role in tumor immune evasion and patient prognosis.