Cross-cancer insights—such as CISD2-mediated iron homeostasis in HNSCC, GLS-driven glutamine metabolism in breast cancer, NT5E-associated purine signaling in pancreatic tumors, and efferocytosis-related immune evasion in glioblastoma—underscore how microenvironmental dysregulation can drive radioresistance and recurrence (30–33). This evidence concerns the gene GLS and head and neck squamous cell carcinoma.