Interestingly, GSEA of patients with the top and bottom 25% SLC1A5 (ASCT2) expression levels in the TCGA HNSCC project showed significantly enriched gene sets of ‘HALLMARK_DNA_REPAIR’, ‘KEGG_BASE_EXCISION_REPAIR’ and ‘KEGG_MISMATCH_REPAIR’ in the high ASCT2 expression group, indicating that ASCT2 and the associated glutamine uptake may play an important role in DNA repair, which is critical for cell survival (Fig. 3e, Tables S2–3). Here, SLC1A5 is linked to head and neck squamous cell carcinoma.