Analysis of Soluble Programmed Death-1 Ligand-1 of Lung Cancer Patients with Different Characteristics

OBJECTIVE: To analyze the association of soluble programmed death-1 ligand-1 (sPD-L1) levels with clinicopathological characteristics, therapy efficacy, and survival outcomes in lung cancer patients. PATIENTS AND METHODS: The study included two hundred treatment-naive patients with small cell lung cancer (SCLC) (n=12), and non-small cell lung cancer (NSCLC) (n=188). Plasma samples from 96 healthy individuals and 13 patients with benign tumors served as controls. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate sPD-L1 expression. Blood samples of 67 NSCLC patients before and after therapy were collected. RESULTS: sPD-L1 expression was significantly higher in lung cancer patients compared to the control groups (p=0.002). Moreover, patients with lower performance status had significantly higher sPD-L1 levels (p=0.005). NSCLC patients at later stages of the disease had greater sPD-L1 levels than those at the early stages (p<0.001). The presence of epidermal growth factor receptor (EGFR) mutation was not significantly different with higher sPD-L1 expression (p=0.334). Although sPD-L1 levels and progression-free survival (PFS) were linked with excellent response to therapy and advancing disease (p=0.307), no correlation was seen between sPD-L1 decrease and progression free survival (PFS). CONCLUSIONS: Elevated sPD-L1 expression in NSCLC patients was associated with more advanced disease and worse overall health of the patients, suggesting a possible association with a negative clinical response and prognosis. sPD-L1 expression may be influenced by the mutation in EGFR.