(0714) Prognostic Value of Tregs and Immune Checkpoints Expression in Tumor-Draining Lymph Nodes for Oropharyngeal Squamous Cell Carcinoma

Introduction: Oral squamous cell carcinoma (OSCC) poses a significant global health burden with rising incidence trends. Despite aggressive therapeutic interventions, including surgery and adjuvant therapies, OSCC continues to exhibit high recurrence rates, diminishing overall survival (OS). Current prognostic indicators lack precision, highlighting the need for novel markers. This study explores the role of tumor-draining lymph nodes (TDLNs) in OSCC, specifically examining T regulatory cells (Tregs) and immune checkpoint expression on T cells within TDLNs as potential prognostic indicators.

Methods: In total, 49 OSCC patients undergoing sentinel node-assisted elective neck dissection were enrolled. TDLNs were analyzed using flow cytometry to profile immune checkpoint expression (PD-1, CTLA-4, TIGIT, TIM-3, LAG-3) and other markers such as CD69, CXCR5 on CD4+, CD8+, and Tregs. Disease-free survival (DFS) and overall survival (OS) were assessed.

Results: According to multivariate analysis, elevated levels of FoxP3+CD4+ and TIGIT+CD8+ cells in TDLNs correlated with significantly worse DFS, while high CXCR5+CD4+ levels were associated with better DFS. Notably, the expression of immune checkpoints on T cells within TDLNs showed significant associations with recurrence status. Patients experiencing recurrence exhibited heightened levels of CD4+PD-1+, CD4+TIGIT+, CD4+CTLA-4+, and CD8+TIGIT+ cells in TDLNs. Conversely, patients without recurrence demonstrated higher CD4+CXCR5+ levels. Survival multivariate analyses revealed that T status emerged as an independent predictor of OS.

Conclusions: This study elucidates the pivotal role of TDLNs in shaping the immunological landscape of OSCC. The identified immune checkpoint expressions on T cells within TDLNs provide novel insights into prognostic markers for OSCC, offering potential avenues for personalized therapeutic interventions to mitigate recurrence and improve survival outcomes.