Dynamic Changes in the Immune Microenvironment in Tumor-Draining Lymph Nodes of a Lewis Lung Cancer Mouse Model After Microwave Ablation.

Purpose: Microwave ablation (MWA) is a minimally invasive technique for treating lung cancer. It can induce immune response; however, its effect on the immune microenvironment in tumor-draining lymph nodes (TdLN) is not well understood. This study aims to identify changes in the immune microenvironment in TdLN following MWA in a Lewis lung cancer (LLC) mouse model. Methods: LLC mouse model was established and followed by MWA. TdLN were collected at various time points, including pre-MWA and days 1, 2, 4, and 8 post-MWA. Flow cytometry was used to determine the frequencies of CD4+ T cells, CD8+ T cells, regulatory T (Treg) cells, natural killer (NK) cells, dendritic cells (DCs) and other immune cells in the TdLN. Certain cytokines were also detected. Results: Compared with pre-MWA, the frequency of CD4+ T cells significantly increased from day 1 to day 8 post-MWA. The frequency of CD8+ T cells decreased significantly on days 2 and 4, but no significant changes occurred on days 1 and 8. Significant decreases in the frequencies of Treg cells and Klrg1+ Treg cells were observed from day 1 to day 4. On days 4 and 8, there was a significant increase in the frequency of NK cells. The frequency of resident cDC2 significantly increased on day 4, whereas CD11b+ migratory cDCs increased on day 1. Additionally, on day 4, a notable rise was observed in the frequency of NK cells secreting IFN-γ, while on day 8, there was a significant increase in the frequency of CD8+ T cells secreting both IFN-γ and TNF-α. Conclusion: MWA of lung cancer can alter the immune microenvironment in the TdLN, triggering immune responses. These changes are particularly evident and intricate within the initial 4 days post-MWA. Treatment combined with MWA within a certain period may significantly enhance anti-tumor immunity.

Immunomodulatory effects of microwave ablation on malignant tumors.

Image-guided thermal ablation (IGTA) is an important treatment modality for interventional oncology. It is widely used for the treatment of solid tumors, such as liver, lung, breast, kidney, and thyroid cancers. IGTA include radiofrequency ablation, microwave ablation (MWA), cryoablation, and laser ablation. Compared with other energy sources, MWA has the advantage of a large ablative volume, short ablative time, and a low heat sink effect. MWA can also induce antitumor immunity; however, only a minority of patients derive a clinical benefit from it. Based on these data, the combination of MWA and immunotherapy has emerged as a promising new direction for cancer treatment. This review article focuses on current research on the combination of MWA and immunotherapy. The status of immune activation and related studies involving MWA for the treatment of various malignant tumors are discussed.

Stem-like CD8 T cells in stage I lung adenocarcinoma as a prognostic biomarker: A preliminary study.

OBJECTIVES: This study aimed to investigate the presence of stem-like CD8 T (CD8 TSL) cells in lung adenocarcinoma (LUAD) and explore their relationships with the clinical outcomes. METHODS: Multiplex immunofluorescence (mIF) was performed to identify CD8 TSL and antigen-presenting cells (APC) in 76 LUAD patients. Differences in the number of CD8 TSL cells based on tumor stage and the spatial relationships between CD8 TSL cells and APC niches were determined. The optimal cutoff value of CD8 TSL cells for predicting survival in patients with stage I LUAD was calculated. RESULTS: CD8 TSL cells were present in all tumors, and their numbers were significantly higher in stage I patients than in stage III patients (P = 0.010); CD8 TSL cells located in the APC niches accounted for 69.7% (53/76) of the hotspot fields. The optimal cutoff value for the number of CD8 TSL cells required to predict the overall survival (OS) in patients with stage I LUAD was 2.5 per 10000 µm2. The median OS and progression-free survival (PFS) in the high-level group (>2.5) were significantly (P < 0.001) longer than those in the low-level group (≤2.5). The number of CD8 TSL cells was an independent prognostic factor for stage I LUAD. Patients with more CD8 TSL cells had a lower risk of death and disease progression than those with less CD8 TSL cells. CONCLUSION: CD8 TSL cells were observed in patients with stages I-III LUAD and might serve as prognostic biomarkers for stage I LUAD.