Oxidative DNA damage and antioxidant vitamin level: comparison among lung cancer patients, healthy smokers and nonsmokers.

In the present study, we examined whether the level of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in leukocyte DNA is higher in lung cancer patients compared to controls. Factors that may influence oxidative stress, such as antioxidant vitamins, were also determined. These parameters were analyzed in 4 groups of subjects: smokers with lung cancer, ex-smokers with lung cancer, healthy smokers with comparable smoking status and healthy nonsmokers. The 8-oxodGuo mean level in leukocytes of lung cancer patients reached values of 9.22/10(6) dGuo molecules (smokers) and 11.16/10(6) dGuo molecules (ex-smokers). These values were significantly higher than in DNA of healthy smokers and nonsmokers, where mean levels reached 6.99/10(6) dGuo molecules and 5.98/10(6) dGuo molecules, respectively. Mean levels of vitamin C in the plasma of controls and lung cancer patients were 56.17 microM (nonsmokers), 26.34 microM (healthy smokers), 23.83 microM (cancer patients, smokers) and 29.19 microM (cancer patients, ex-smokers). The difference between nonsmokers and the 3 other groups was statistically significant. Vitamin E level was significantly reduced in the plasma of cancer patients (smokers 19.94 microM, ex-smokers 19.59 microM) compared to healthy smokers (28.93 microM). No changes in vitamin A concentration were found. Our results suggest that a high level of 8-oxodGuo in leukocyte DNA and a low concentration of vitamin E in the blood may predict lung cancer risk. However, it is also possible that these phenomena may simply result from disease development.