ESMO Open. 2025 Aug 12;10(8):105538. doi: 10.1016/j.esmoop.2025.105538. Online ahead of print.
ABSTRACT
BACKGROUND: HRAS mutations define a distinct biologic subset of head and neck squamous-cell carcinoma (HNSCC). There are limited data regarding HRAS-mutant (mut) tumors’ sensitivity to immunotherapy. We sought to evaluate the mutational landscape and transcriptional profile, as well as analyze the tumor microenvironment (TME) of HRAS-mut tumors to provide the conceptual framework for combinatorial treatment approaches.
MATERIALS AND METHODS: We analyzed mutational and transcriptome data from The Cancer Genome Atlas (TCGA). In addition, genomic DNA from baseline tumor biopsies was targeted for sequencing. Our study included 10 patients with HRAS-mut and 40 with HRAS-wild-type (WT) HNSCC. Programmed death-ligand 1 (PD-L1) expression in formalin-fixed paraffin-embedded tumor samples was assessed using the PD-L1 IHC 22C3 pharmDx assay. We characterized subpopulations of exhausted CD8(+) T cells by measuring the expression of T-cell factor-1 (TCF1) and programmed cell death protein 1 (PD-1) in both the center and the periphery of the tumors using multiplex immunohistochemistry, followed by analysis using a manually trained algorithm in QuPath software.
RESULTS: The analysis of TCGA HNSCC mutation and mRNA expression data demonstrated that 6% of HNSCCs harbor mutant HRAS. Transcriptome analysis showed that HRAS-mut HNSCCs are infiltrated by immune cells (CD8A, CD8B, CD2) and have higher expression levels of CXCL11, CXCL10, CXCL9 and CCL4 chemokines. Moreover, the percentage of HRAS-mut samples increased in higher PD-L1 score groups (11% versus 20% versus 100% in tumor positive scores <1%, 1%-49% and ≥50%, respectively, P = 0.006). The analysis of TME showed that HRAS-mut tumors have a statistically significant higher number of total immune cells (5123.17/mm2 versus 3527.93/mm2, P = 0.002) and a higher percentage of pre-exhausted CD8(+) PD-1(+) TCF1(+) T cells in the periphery (384.67/mm2 versus 51.18/mm2, P = 0.040) than HRAS-WT tumors.
CONCLUSIONS: HRAS-mut HNSCCs are characterized by a significantly increased number of pre-exhausted PD-1(+) TCF1(+) T cells and PD-L1 expression, suggesting a potential sensitivity to immunotherapy.
PMID:40803018 | DOI:10.1016/j.esmoop.2025.105538
