An entosis-anchored hybrid prognostic signature identifies immunotherapy-resistant subgroups in head and neck squamous cell carcinoma

BACKGROUND: Entosis is a non-apoptotic form of cell-in-cell death implicated in tumor progression and immune evasion. However, the prognostic and immunological significance of entosis-related genes in head and neck squamous cell carcinoma (HNSCC) has not been systematically studied. This study aimed to construct and validate an entosis-anchored hybrid prognostic signature for HNSCC and to characterize its association with the tumor immune microenvironment and therapeutic response. METHODS: Gene expression and clinical data of 565 HNSCC patients from The Cancer Genome Atlas (TCGA) were used as the discovery cohort, randomly split into training (n = 396) and testing (n = 169) sets. A hybrid strategy integrating entosis pathway genes with genome-wide candidates was employed to construct a 14-gene prognostic signature via LASSO-Cox regression. External validation was performed in GSE65858, GSE41613, and CPTAC cohorts, with a fixed-effect meta-analysis synthesizing the results. Immune infiltration, immune checkpoint expression, TIDE-based immune evasion, drug sensitivity (oncoPredict/GDSC2 cell-line data), and a clinical nomogram were also evaluated. RESULTS: The 14-gene entosis-anchored signature (ERS-14) comprised four entosis core genes (MYL2, CDKN2A, LAMP1, SPP1) and ten genome-wide prognostic genes. In the TCGA cohort, ERS-14 achieved a concordance index (C-index) of 0.703 and time-dependent AUC values of 0.737, 0.739, and 0.725 at 1, 3, and 5 years, respectively. Meta-analysis across external cohorts confirmed its prognostic value (HR = 1.551, 95% CI 1.147-2.096, p = 0.004, I² = 0%). Multivariate Cox regression demonstrated that ERS-14 was an independent predictor (HR = 4.362, p < 2 × 10⁻²⁰), and subgroup analysis revealed consistent prognostic performance across all 13 clinical subgroups tested. The high-risk group exhibited a T cell exclusion phenotype characterized by elevated cancer-associated fibroblast (CAF) scores (p = 0.008), downregulated immune checkpoints, and significantly increased resistance to cisplatin (p = 0.0001) and multiple targeted agents. CONCLUSIONS: We developed and validated ERS-14, an entosis-anchored hybrid prognostic signature in HNSCC that predicts survival, identifies an immunosuppressive microenvironment driven by T cell exclusion, and reveals therapeutic vulnerabilities that may inform treatment selection.