Tongue squamous cell carcinoma (TSCC), a subtype of head and neck squamous cell carcinoma, is characterized by frequent chemoresistance. Genetic mutations commonly observed in TSCC play a critical role in malignant progression
thus, elucidating their functional significance is essential for developing effective treatment strategies. To more accurately investigate the relationship between mutations and chemoresistance, we established low-passage TSCC cells, CTSC-1, obtained from a chemoresistant patient, and CTSC-2, from a treatment-naïve patient. Sanger sequencing revealed a specific TP53 mutation (Q331*) in CTSC-1, leading to the loss of the tetramerization and C-terminal regulatory domains. Notably, CTSC-1 cells harboring TP53-Q331* and CTSC-2 cells with TP53 knockout that have been engineered to ectopically express TP53-Q331* exhibit enhanced chemoresistance and increased cancer stem cell-like properties. Mechanistically, TP53-Q331* upregulates the expression of inhibitor of DNA binding 2 (ID2), which is crucial for maintaining the stemness of TSCC cells. Subsequently, ID2 activates the expression of nucleotide excision repair (NER) pathway-related genes ERCC4 and ERCC8, thereby enhancing the chemoresistance in TSCC. In conclusion, our study demonstrates that the TP53-Q331* mutation enhances TSCC chemoresistance through an ID2-mediated NER pathway, providing a potential prognostic marker and therapeutic target for TSCC chemotherapy resistance.