Association of PD‐L1 Expression With Tertiary Lymphoid Structures and Prognosis in Oral Cancer

Background Tertiary lymphoid structures (TLSs) are observed within invasive regions of malignancies. This study aimed to elucidate the relationship between programmed death‐ligand 1 (PD‐L1) expression and TLSs in oral squamous cell carcinoma (OSCC) and to assess their prognostic significance. Methods A total of 280 OSCC cases were analyzed. PD‐L1 expression was assessed via immunohistochemistry using biopsy and surgical specimens. Staining for immune cells was performed in cases exhibiting TLSs. Results Patients with high PD‐L1 expression and the presence of TLSs demonstrated significantly improved overall survival ( p < 0.05). In contrast, in cases with low PD‐L1 expression, the presence of TLSs was associated with significantly poorer overall survival ( p < 0.05). Conclusion OSCC cases with TLSs, high PD‐L1 expression is associated with a favorable prognosis, whereas low PD‐L1 expression correlates with significantly worse outcomes. This suggests that TLSs may be functionally heterogeneous, with distinct prognostic implications depending on PD‐L1 expression.