Il‐17 promotes nitric oxide production in non‐small‐cell lung cancer

Introduction: Lung cancer is the second most frequent malignancy worldwide, but its aetiology is still unclear. Inflammatory cytokines and Th cells, including Th17, are now emerging as being involved in NSCLC pathways, thus postulating a role of IL‐17 in tumour angiogenesis by stimulating the vascular endothelial growth factor and the release of nitric oxide. Despite the fact that many biomarkers are used for chest malignancy diagnosis, data on FeNO levels and inflammatory cytokines in NSCLC are still few. Our study aimed to evaluate the relationship between pulmonary nitric oxide production and VEGF and Th17‐related cytokines in the EBC of patients affected by early‐stage NSCLC. Methods: FeNO measurement and lung function tests were performed in both patients affected by NCSLC and controls; EBC samples were also taken, and Th1 (IL‐1, IL‐6, IL‐12, IFN‐g, TNF‐a), Th17 (IL‐17, IL‐23) and Th2 (IL‐4, IL‐5, IL‐13) related cytokines were measured. Results: Th1 and Th17‐related cytokines in EBC, except for IFN‐gamma and TNF-alpha, were significantly higher in patients than in healthy controls, whereas no differences were seen for Th2‐related cytokines. FeNO at the flow rate of 50 mL/s, JawNO and CalvNO levels were significantly higher in patients affected by NSCLC compared to controls. Significant correlations were found between FeNO 50 mL/s and IL‐17, IL‐1 and VEGF. JawNO levels positively correlated with IL‐6, IL‐17 and VEGF. No correlations were found between FeNO and Th2‐related cytokines. Conclusion: This is the first report assessing a relationship between FeNO levels and Th17‐related cytokines in the EBC of patients affected by early‐stage NSCLC. IL‐17, which could promote angiogenesis through the VEGF pathway, might be indirectly responsible for the increased lung production of NO in patients with NSCLC.