Elevated TMC8 expression correlates with CD8⁺ T cell infiltration and favorable survival in oral squamous cell carcinoma

Background: Oral squamous cell carcinoma (OSCC) outcomes are fundamentally dictated by complex interactions within the tumor immune microenvironment. Elevated expression of transmembrane channel-like 8 (TMC8) has been correlated with favorable survival across various solid tumors. However, it remains undetermined whether this prognostic benefit reflects a tumor-suppressive cellular function or a broader microenvironmental crosstalk. This study aimed to investigate the cell-autonomous role of TMC8 in OSCC and explore its broader immunological crosstalk within the tumor microenvironment (TME).

Methods: The present study integrated large-scale immunogenomic analyses of 315 clinical samples with in vitro functional assays and topological network mapping. Targeted gene silencing in pure OSCC cell lines was conducted to evaluate cell-autonomous behaviors, including proliferation and invasion. The macroscopic immunological landscape was stratified utilizing multidimensional deconvolution algorithms, and the predicted intercellular communication was explored through protein-protein interaction networks and unsupervised co-expression matrices.

Results: While TMC8 was significantly upregulated in malignant tissues, elevated expression strongly predicted prolonged overall and progression-free survival. In vitro assessments demonstrated that silencing this target attenuated malignant cellular phenotypes, suggesting a pro-tumorigenic role in vitro. Conversely, clinical macro-omics analyses revealed that elevated expression of this transmembrane protein was strongly associated with a CD8⁺ T cell-enriched inflamed microenvironment. Bioinformatics network mapping predicted that TMC8 was co-expressed and potentially associated with the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) innate sensing network and subsequent inflammatory cascades, rather than functioning as a direct source of terminal chemokines.

Conclusions: The intrinsic cellular pro-tumorigenic role of TMC8 might be counterbalanced by its potential association with danger-sensing networks. This potential network association could be linked to a multicellular inflammatory crosstalk that correlates with cytotoxic T lymphocyte recruitment, providing a plausible hypothesis for the paradoxical survival benefit and highlighting its value as a prognostic biomarker.