EVALUATION OF MEMBRANE AND SOLUBLE PD-L1 EXPRESSION IN ADVANCED-STAGE NON-SMALL CELL LUNG CANCER PATIENTS

Objectives: To evaluate membrane and soluble PD-L1 expression in advanced-stage non-small cell lung cancer (NSCLC) patients. Subjects and methods: A prospective, cross-sectional study on 50 advanced-stage NSCLC patients treated at the Respiratory Center, Military Hospital 103 from January to September 2019; the control group consists of 30 normal people who had personal periodic health examination at the Outpatient Department, Military Hospital 103. Membrane PD-L1 (mPD-L1) expression assay was carried out applying immunohistochemistry on cancer tissue samples, using PD-L1 73 - 10 antibody. The serum level of soluble PD-L1 (sPD-L1) was measured using the ELISA technique. Results: 62% of lung cancer tissue samples were positive for mPD-L1 (TPS ³ 1%), of which 51.6% were highly positive and 48.4% low positive. The concentration of sPD-L1 in NSCLC group was significantly higher than that of the control group (2.11 ± 1.48 and 0.73 ± 0.57 ng/mL; p < 0.001). sPD-L1 concentration in the mPD-L1 negative group (1.61 ± 1.37 ng/mL) was statistically significantly lower than that in the mPD-L1 positive group               (2.42 ± 1.49 ng/mL) (p = 0.03). At the cut-off value of 1.815 ng/mL, sPD-L1 had a diagnostic value for mPD-L1 positive with a sensitivity of 65% and specificity of 68%, area under the curve was 0.678 (95% CI: 0.521 - 0.835; p = 0.036). Conclusion: The rate of mPD-L1 positive expression in NSCLC tissue was 62%. The concentration of sPD-L1 in NSCLC patients was significantly higher than that in the control group. No significant relationship was found between the two forms of PD-L1 expression.