Tertiary lymphoid structures (TLS) are ectopic lymphoid structures in cancers that are largely associated with favourable prognosis. However, the prognostic value of TLSs in oral squamous cell carcinoma (OSCC) is largely unknown, and the association between tumour infiltrating lymphocytes (TILs) and TLSs has been rarely explored in OSCC. In this study, associated markers of TLS, including peripheral node address (PNAd) in high endothelial venules, CD20 in B cells and CD3 in T cells, were examined in 168 OSCC patients, and survival analysis was performed between TLS-positive and TLS-negative cohorts. We detected the presence of TILs by staining CD8+ cytotoxic T cells and CD57+ NK cells as well. TLSs appeared as highly organized structures in 45 (26.8%) cases. TLS-positive patients had a better 5-year overall survival (OS) rate (88.9% vs. 56.1%, P < 0.001) and relapse-free survival (RFS) rate (88.9% vs. 63.4%, P = 0.002). Moreover, the presence of TLS was an independent prognostic factor for both the 5-year OS rate (hazard ratio [HR] = 3.784; 95% confidence interval [CI], 1.498-9.562) and RFS rate (HR = 3.296; 95% CI, 1.279-8.490) in multivariate analysis. Furthermore, a higher density of CD8+ T cells and CD57+ NK cells was found in TLS-positive sections than in TLS-negative counterparts (P < 0.001), and their combination provided a higher predictive accuracy (AUC = 0.730; 95% CI, 0.654-0.805). In conclusion, our results suggest that TLS is an independent positive prognostic factor for OSCC patients. These findings provide a theoretical basis for the future diagnostic and therapeutic value of TLSs in OSCC treatment.

The heterogeneity of exhausted T cells (Tex) is a critical determinant of immune checkpoint blockade therapy efficacy. However, few studies have explored exhausted T cell subpopulations in human cancers. In the present study, we examined samples from two cohorts of 175 patients with head and neck squamous cell cancer (HNSCC) by multiplex immunohistochemistry (mIHC) to investigate two subsets of Tex, CD8⁺PD1⁺TCF1⁺ progenitor exhausted T cells (TCF1⁺Tex^prog) and CD8⁺PD1⁺TCF1^- terminally exhausted T cells (TCF1^-Tex^term). Moreover, fresh tumor samples from 34 patients with HNSCC were examined by flow cytometry and immunohistochemistry to further investigate their properties and cytotoxic capabilities and their correlation with regulatory T cells (Tregs) in the tumor immune microenvironment (TIME). mIHC and flow cytometry analysis showed that TCF1^-Tex^term represented a greater proportion of CD8⁺PD1⁺Tex than TCF1⁺Tex^prog in most patients. TCF1⁺Tex^prog produced abundant TNFα, while TCF1^-Tex^term expressed higher levels of CD103, TIM-3, CTLA-4, and TIGIT. TCF1^-Tex^term exhibited a polyfunctional TNFα⁺GZMB⁺IFNγ⁺ phenotype; and were associated with better overall survival and recurrence-free survival. The results also indicated that larger proportions of TCF1^-Tex^term were accompanied by an increase in the proportion of Tregs. Therefore, it was concluded that TCF1^-Tex^term was the major CD8⁺PD1⁺Tex subset in the HNSCC TIME and that these cells favor patient survival. A high proportion of TCF1^-Tex^term was associated with greater Treg abundance.
CD8-Positive T-Lymphocytes ; Head and Neck Neoplasms/therapy* ; Humans ; Immunotherapy/methods* ; Prognosis ; Programmed Cell Death 1 Receptor ; Squamous Cell Carcinoma of Head and Neck/therapy* ; Tumor Microenvironment ; Tumor Necrosis Factor-alpha