Elevated Tumor Cell-Intrinsic STING Expression in Advanced Laryngeal Cancer

SIMPLE SUMMARY: Novel therapeutic approaches are required to improve the outcomes of immunotherapy for laryngeal cancer. The immunomodulatory effects of the DNA sensor cGAS and the cyclic GMP–AMP receptor stimulator of interferon genes (STING) signaling axis have been extensively studied in various types of cancer; however, their role in laryngeal cancer remains unknown. The findings of this study demonstrated that STING is upregulated in immunologically active advanced laryngeal cancer. Targeting the STING–cGAS signaling pathway in laryngeal cancer might potentially improve current therapeutic approaches, and elevated STING expression could be considered as a predictive biomarker in future clinical trials, including STING agonists. ABSTRACT: Laryngeal cancer is the second most common malignancy of the head and neck, worldwide. Immunotherapy targeting checkpoint inhibitors has been approved for the treatment of patients with recurrent or metastatic laryngeal cancer but has a relatively low response rate and outcomes that leave many patients underserved. Targeting the cGAS–STING signaling pathway can potentially improve the activation of immune effector cells, although its role in the development and progression of laryngeal cancer has not yet been investigated in depth. Fifty-nine tumor samples from patients with pathologically confirmed squamous cell carcinoma of the larynx, stage I–IV non-metastatic disease, who were treated at the University Hospital of Split, were immunohistochemically stained for the expression of STING, cGAS, CD8, CD68, and CD163. Elevated tumor cell-intrinsic STING expression was positively associated with stage IV (p = 0.0031), pT3, and pT4 laryngeal cancers (p = 0.0336) as well as with higher histological grades (G2 and G3) (p = 0.0204) and lymph node-positive tumors (p = 0.0371). After adjusting for age, sex, location, and cGAS expression, elevated STING expression was significantly associated with stage IV cancer in a multiple logistic regression model (β = 1.849, SE = ±0.8643, p = 0.0324). Elevated STING expression represents a potentially favorable predictive biomarker for new therapeutic approaches involving STING agonists combined with immunotherapy and DNA-damaging agents (radiotherapy, cisplatin, and PARP inhibitors) in laryngeal cancer.