Evaluation of Oxidative Stress Biomarkers in Brain Metastatic and Non-Metastatic Lung Cancer Patients with Different Cell Types

Background: Oxidative stress that leads to an imbalanced prooxidant/antioxidant status can be a critical factor affecting lung cancer etiopathology. The antioxidant system provides primary protection under oxidative stress. Objective: The purpose of the study was to investigate the serum antioxidant system status in brain metastatic and non-metastatic lung cancer patients with different cell types. Methods: In this prospective study, 33 patients with lung cancer metastasis (metastatic patient group), 36 lung cancer patients (non-metastatic patient group), and 25 healthy control groups were included. Enzymatic (Superoxide Dismutase, SOD; Glutathione Peroxidase, GPX; and Glutathione Reductase, GR) and non-enzymatic (Glutathione, GSH) antioxidant system biomarkers with Thiobarbituric Acid Reactive Substances (TBARS) levels were studied in the serum samples of the control and patient groups. The oxidative stress biomarkers were measured spectrophotometrically. Results: SOD activity increased though TBARS levels and GR activity decreased in both patient groups compared to the control. GPX activity increased only in the non-metastatic group. Antioxidant biomarkers varied between small cell and non-small cell group patients. GR activity and GSH levels were significantly higher in the non-metastatic group compared to the metastatic group. Correlations were also found between antioxidant parameters in the non-metastatic group. Conclusion: It was emphasized the imbalanced antioxidant system in the duration of the disease is related to not only cell type but also the metastatic structure. This is the preliminary study exhibiting the contribution of antioxidant imbalance in different subtypes with varied prognosis and behavior of lung cancer in the presence of brain metastasis. Therefore, oxidative stress biomarkers can serve as a useful tool to get information about the progression of lung cancer. Thus, it may provide fundamental data for further cancer research when considering the diagnosis of the disease.