[TIM3+CD8+ T Cell Expression and Clinical Significance in the Central and Non-central Tumor Microenvironment of Non-small Cell Lung Cancer].

Abstract

Background: One of the most important treatment modalities for non-small cell lung cancer (NSCLC) is immune checkpoint inhibitor. Nevertheless, a small percentage of patients do not respond well to these therapies, highlighting the significance of identifying important CD8+ T cell subsets for immunotherapy and creating trustworthy biomarkers. The purpose of this study is to assess the potential utility of TIM3+CD8+ T cells as new biomarkers by examining their expressions in various areas of the NSCLC tumor microenvironment.

Methods: Based on biopsy techniques, tumor tissue samples were obtained from patients with NSCLC and categorized into tumor central and non-central regions. Using flow cytometry, the infiltration of TIM3+CD8+ T cells and the surface expression of programmed cell death 1 (PD-1) on these cells were examined, and their correlations with the effectiveness of immunotherapy were assessed.

Results: The non-central region of tumor tissues had considerably larger infiltration of TIM3+CD8+ T lymphocytes compared to the non-central region (P<0.0001). This pattern was found in both subgroups with tumor diameters ≥3 cm or <3 cm (P<0.01). In comparison to TIM3-CD8+ T cells, TIM3+CD8+ T cells showed higher levels of PD-1 (P<0.001), with more PD-1+TIM3+CD8+ T cells invading the non-central region (P<0.01). Clinical responders to immunotherapy had considerably lower infiltration levels of TIM3+CD8+ T cells in the tumor non-central region compared to non-responders, with lower levels correlated with better clinical outcomes (P<0.01), while no correlation was identified in the tumor central region (P>0.05). According to reciever operating characteristic (ROC) curve analysis, TIM3+CD8+ T cells in the tumor non-central region had an area under the curve (AUC) of 0.9375 for predicting the effectiveness of immunotherapy, which was considerably higher than that of TIM3+CD8+ T cells in the tumor central region and programmed cell death ligand 1 (PD-L1) [tumor proportion score (TPS)].

Conclusions: In the tumor microenvironment of NSCLC, TIM3+CD8+ T cells show regional distribution patterns. The expression of this cell population in the non-central region of the tumor microenvironment may be a biomarker for predicting the effectiveness of immunotherapy.