The biological characteristics of tertiary lymphoid structures in head and neck cancer.

Head and neck cancer (HNC) is one of the most prevalent malignancies worldwide, and its clinical management remains fraught with formidable challenges. In recent years, as our understanding of the tumor microenvironment (TME) has deepened, immunotherapy-especially the clinical application of immune checkpoint inhibitors (ICIs)-has brought a revolutionary breakthrough to HNC treatment. However, only a subset of patients can derive clinical benefits from such therapies, highlighting the urgent need to identify reliable predictive biomarkers. Tertiary lymphoid structures (TLS), lymphocyte aggregates ectopically formed in non-lymphoid tissues such as chronically inflamed or tumor sites with functions analogous to secondary lymphoid organs, have emerged as a burgeoning research hotspot in tumor immunology. This review aims to systematically elaborate on the biological characteristics of TLS in HNC, their clinical value as biomarkers for prognostic evaluation and immunotherapy response prediction, current TLS detection and assessment methodologies, as well as potential therapeutic strategies targeting TLS. We employed a systematic literature review methodology. Studies have confirmed that mature, intra-tumoral TLS are significantly correlated with improved patient prognosis and higher immunotherapy response rates, acting as the "central core" of tumor immunity by initiating and sustaining adaptive anti-tumor immune responses locally. Despite the promising clinical translation prospects of TLS, standardization of assessment systems, development of non-invasive detection technologies, and clarification of TLS functional heterogeneity across different HNC subtypes remain major challenges in current research. This review synthesizes the latest advances in this field, providing a comprehensive and insightful perspective for understanding the pivotal role of TLS in HNC treatment.