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.

Globally, bladder cancer is the sixth most frequently diagnosed cancer among men. Despite the increasing availability of immunomodulatory treatments for bladder cancer, the survival rates are still low, which calls for potential new drug-repurposing targets. This study aimed to investigate the effects of cromolyn, a mast cell (MC) stabilizer in allergic reactions, on a subcutaneous tumor model with a syngeneic mouse MB49 bladder cancer cell line. A concentration of 50 mg/kg of cromolyn was daily administered intraperitoneally in a 4-day therapeutic protocol to mice with established tumors and in a continuous 11-day protocol which started one day prior to the subcutaneous injection of tumor cells. Therapeutic treatment demonstrated a marked downregulation of genes related to angiogenesis and upregulation of genes related to cytotoxic T-cell and NK cell activity. Conversely, continuous cromolyn treatment suppressed genes involved in immune cell recruitment and activation, as well as apoptotic and necroptotic pathways, leading to a greater tumor burden (+142.4 mg [95CI + 28.42, +256.4], p = 0.0158). The same pro-tumorigenic effect was found in mast cell-deficient mice (Kit^W-sh/W-sh + 301.7 mg [95CI + 87.99, 515.4], p = 0.0079; Cpa3^Cre/+ +107.2 mg [95CI − 39.37, +253.57], p = 0.1423), indicating that continuous cromolyn treatment mostly acts through the inhibition of mast cell degranulation. In summary, our results demonstrate the distinct effects of cromolyn on tumor progression, which depend on the protocol of cromolyn administration.