The Inflammatory-Oxidative Axis in Lung Cancer: A Comprehensive Review of Serum C-Reactive Protein, Nitric Oxide, Superoxide Dismutase, Glutathione Reductase, and Glutathione Peroxidase Alterations.

Lung cancer remains the leading cause of cancer-related mortality worldwide, accounting for approximately 1.8 million deaths annually. Despite advances in targeted therapies and immunotherapy, late diagnosis and therapeutic resistance continue to limit patient outcomes. Emerging evidence implicates systemic inflammation and oxidative stress as critical drivers of lung cancer initiation, progression, and treatment resistance. This comprehensive review synthesizes current knowledge regarding alterations in serum C-reactive protein (CRP), nitric oxide (NO), superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) in patients with lung cancer. A consistent body of literature demonstrates significantly elevated CRP and NO levels alongside markedly reduced SOD, GR, and GPx activities in treatment-naïve patients with lung cancer compared to healthy controls, indicating a profound inflammatory-oxidative imbalance. However, important heterogeneity exists across studies, with the magnitude of these alterations varying by tumor stage, histological subtype, smoking history, and the biological compartment analyzed. The absence of linear correlation between inflammatory and antioxidant markers in several studies suggests complex, non-linear interactions between these pathways rather than simple opposition. Clinically, this combined biomarker panel may aid in risk stratification, disease monitoring, and evaluation of therapeutic response, particularly when integrated into established scoring systems such as the Glasgow Prognostic Score. Major knowledge gaps persist, including a lack of large prospective longitudinal studies, the absence of validated cut-off values, and limited correlation with hard clinical endpoints. Future research should prioritize multicenter cohorts with standardized assays and paired serum-tissue analyses to translate this axis into routine oncologic practice.