Serum Copper Level and the Copper-to-Zinc Ratio Could Be Useful in the Prediction of Lung Cancer and Its Prognosis: A Case-Control Study in Northeast China

BACKGROUND: The association between lung cancer and trace element levels, such as serum copper (Cu) and zinc (Zn) levels and the Cu:Zn ratio, vary among different demographic groups; however, it is unknown whether variations in serum Cu and Zn levels and Cu:Zn ratios are related to the prediction and prognosis of lung cancer. We aimed to clarify this relationship in the Han Chinese population of Northeast China. METHODS: We recruited 146 patients with lung cancer and 146 age- and resident area-matched cancer-free controls. RESULTS: Increased serum Cu and Zn levels and the Cu:Zn ratio were positively associated with lung cancer (OR: 72.243, 95% CI 24.159-216.030; OR: 3.513, 95% CI, 1.476-8.358, and; OR: 58.582, 95% CI, 20.023-171.395, respectively). The critical serum Cu level for the prediction of lung cancer was 1.37 mg/L (sensitivity, 77.4%; specificity, 84.9%), while the critical Cu:Zn ratio was 1.45 (sensitivity, 69.9; specificity, 88.4%). Patients with stage IV non-small-cell lung cancer (NSCLC) had higher serum Cu levels and a higher Cu:Zn ratio than patients with stage I, II, or III NSCLC. CONCLUSIONS: The serum Cu level and the Cu:Zn ratio are effective predictive indicators of lung cancer and may help evaluate the prognosis of patients with NSCLC.