关键词: 髓系来源抑制性细胞, 非小细胞肺癌, PD-1抑制剂, 化疗, 疗效

Abstract: AIM: To explore the relationship between the level of myeloid-derived suppressor cell (MDSC) infiltration in tumor tissues and the clinical efficacy and prognosis of combined PD-1 inhibitor and chemotherapy in the treatment of advanced non-small cell lung cancer (NSCLC). METHODS: A retrospective analysis was conducted on 92 NSCLC patients who received PD-1 inhibitor combined with chemotherapy at the First Affiliated Hospital of Anhui Medical University from June 2019 to June 2024. Tumor tissue samples were examined using immunohistochemistry to detect the level of MDSC infiltration, dividing the patients into high-infiltration group (MDSC≥2) and low-infiltration group (MDSC<2). The objective response rate (iORR), disease control rate (iDCR), progression-free survival (PFS), and overall survival (OS) were compared between the two groups. Kaplan-Meier survival analysis and Log-rank test were used to plot PFS and OS survival curves, and Cox regression analysis was applied to identify factors influencing prognosis. RESULTS: Among the 92 patients, 53 were in the low MDSC infiltration group, and 39 were in the high MDSC infiltration group. The low MDSC infiltration group showed significantly better treatment responses compared to the high MDSC infiltration group. The objective response rate (iORR) was 77.3% in the low MDSC infiltration group, higher than the 56.4% in the high MDSC infiltration group (P=0.033). The disease control rate (iDCR) was 94.3%, also significantly higher than the 66.7% in the high MDSC infiltration group (P=0.001). Moreover, the median progression-free survival (PFS) and overall survival (OS) in the low MDSC infiltration group were 16.9 months and 27.6 months, respectively, which were significantly longer than those in the high MDSC infiltration group (PFS 12.6 months, OS 22.3 months). Kaplan-Meier analysis revealed that both PFS and OS in the low MDSC infiltration group were significantly longer than those in the high MDSC infiltration group. Cox univariate analysis showed that smoking, PD-L1 expression levels, tumor stage, and MDSC infiltration level were closely associated with PFS and OS. Multivariate Cox regression analysis further indicated that high MDSC infiltration was an independent risk factor for both PFS (HR=2.678, P=0.013) and OS (HR=2.254, P=0.022). CONCLUSION: The level of MDSC infiltration in tumor tissues is closely related to the efficacy and prognosis of PD-1 inhibitor combined with chemotherapy in NSCLC patients. High MDSC infiltration suggests reduced treatment sensitivity and poor prognosis. MDSC infiltration level may serve as a predictive biomarker for the efficacy and prognosis of PD-1 inhibitor combined with chemotherapy in advanced NSCLC.

Key words: myeloid-derived suppressor cell, non-small cell lung cancer, PD-1 inhibitors, chemotherapy, efficacy