Higher serum nitrate levels are associated with poor survival in lung cancer patients

Objectives: Angiogenic factors induce tumour growth and angiogenesis which leads to tumour metastasis and a poor survival rate. This study aimed to assess the possible roles of nitric oxide (NO) and vascular endothelial growth factor-A (VEGF-A) in the overall survival of patients with late stage lung cancer. Design and Methods: The study was carried out with primary lung carcinoma patients (n = 31) and healthy controls (n = 15). Pre- and post-cisplatin-based chemotherapy serum nitrite/nitrate levels were measured as nitrite after enzymatic conversion followed by Griess reaction and serum VEGF-A analysis was performed using ELISA. After patient follow-up, survival rates were calculated by using the Kaplan–Meier method [Dudek et al. Cancer Invest 2005; 23(3):193–200]. Results: The serum nitrite/nitrate and VEGF-A levels of lung cancer patients and the control group were 93.7 ± 48.9 and 63.7 ± 32.2 μM (p = 0.018), and 620 ± 491 and 255 ± 157 pg/mL (p = 0.001), respectively. High nitrite/nitrate (> 67.2 μM) concentration had statistically significant effects on overall survival (Cox analysis, p = 0.026). The overall survival of the lung cancer patients with higher serum nitrate concentrations was significantly less than the ones with lower serum nitrite/nitrate (Kaplan–Meier survival functions test, log rank significance = 0.0007). Conclusion: Our results suggest that having a high serum nitrite/nitrate concentration is a strong indicator of poor survival for late stage lung cancer patients. However, this conclusion deserves to be elucidated further by using a larger sample size.