Non-small cell lung cancer in Chinese is associated with disturbance in systemic antioxidant profiles

Abstract

Introduction Lung cancer, mainly consists of non-small cell carcinoma (NSCLC), has become an epidemic in the past few decades. Recent data have suggested an important role of antioxidants and reactive oxygen species in lung carcinogenesis. However, the exact antioxidant profiles in subjects with NSCLC are lacking. We have conducted a study of the systemic antioxidant activities in red blood cell lysate from subjects with NSCLC and healthy control subjects. Method Antioxidants (catalase, superoxide dismutase [SOD], and glutathione peroxidase [GPx]) were measured using chemical kinetic reactions under spectrophotometry as previously described.1 Results There were 189 cases of mostly advanced stage IIIB or IV NSCLC (67% males, 57.0 ± 11.7 years, 56% ever-smoked, 56% adenocarcinoma) and 202 healthy controls (59% males, 49.5 ± 15.6 years, 39% ever-smoked) being studied. In subjects with lung cancer, there were higher catalase activity (32.6 ± 4.3 vs 23.5 ± 0.9 mU/g haemoglobin (Hb), P = 0.03), lower SOD activity (26.4 ± 2.4 vs 55 ± 2.5 U/gHb, P < 0.001), and higher GPx activity (227.3 ± 12.4 vs 50.8 ± 1.1 mU/gHb, P < 0.001) compared with controls. The antioxidant activities in lung cancer subjects were not associated with age, gender, smoking status, or tumour cell types. However, more advanced disease (stage IV compared to IIIB) was associated with lower SOD activity (21.8 ± 2.5 vs 37.0 ± 5.7 U/gHb respectively, P = 0.03). Using multivariate analysis, the presence of lung cancer independently predicts catalase, SOD, and GPx activities. Conclusion NSCLC in Chinese is associated with alterations in systemic antioxidant activities, which may play an important role in carcinogenesis. (This study is partially funded by the University Department of Medicine Research Grant 2002, the University of Hong Kong.)