Multi-index comprehensive evaluation of the efficacy and response mechanism of immunotherapy in non-small cell lung cancer

Objective This research conducted multi-index comprehensive evaluations of the immunotherapeutic efficacy and response in non-small cell lung cancer (NSCLC). Methods Forty-five patients with epidermal growth factor receptor (EGFR)/anaplastic lymphoma kinase (ALK) wild-type advanced NSCLC who received immunotherapy were included. Immunohistochemistry was adopted to detect the expression levels of programmed death ligand 1 (PD-L1) with X-ray cross-complementing protein 1 (XRCC1) and excision repair cross-complementing group 1 (ERCC1) proteins in tumor tissues. Flow cytometry was utilized to measure the levels of T-cell subsets in peripheral blood before and after treatment. PCR-RELP method was employed to evaluate XRCC1 and ERCC1 gene polymorphisms in peripheral blood. According to the treatment effect, patients evaluated as complete response (CR), partial response (PR), and stable disease (SD) were categorized into the immune response group, and patients evaluated as progressive disease (PD) were categorized into the immune unresponsive group. The correlation between PD-L1 protein expression, XRCC1 and ERCC1 protein expression, gene polymorphisms, T-cell subpopulation levels, and treatment efficacy was analyzed. Results The therapeutic efficacy of patients with positive PD-L1 expression was better than that of patients with negative PD-L1 expression (P < 0.05). After treatment, peripheral blood CD3(+) and CD4(+) cell levels and Thl/Th2 cell levels were higher and CD8(+) T cells were lower in the immune response group than in the immune unresponsive group (P < 0.05). Among the patients in the immune response group, peripheral blood CD3(+) and CD4(+) cell levels were higher and CD8(+) T cells were lower in patients with positive PD-L1 expression than in patients with negative PD-L1 expression (P < 0.05). In the XRCC1 gene, the proportion of patients in the immune response group carrying the Arg/Trp + Trp/Trp genotype was higher than that of patients in the immune unresponsive group (P < 0.05). In the ERCC1 gene, the proportion of patients in the immune response group carrying the C/T + T/T genotype was higher than that of patients in the immune unresponsive group (P < 0.05). The positive expression rates of XRCC1 and ERCC1 in patients in the immune unresponsive group were higher than those in the immune response group (P < 0.05). Conclusion PD-L1 protein expression, XRCC1 and ERCC1 protein expression, and gene polymorphisms are associated with immunotherapy outcome in EGFR/ALK wild-type advanced NSCLC patients, and may be biological indicators for predicting immunotherapy outcome in EGFR/ALK wild-type advanced NSCLC patients.