DECREASED SELENIUM CONCENTRATION AND GLUTATHIONE-PEROXIDASE ACTIVITY IN BLOOD AND INCREASE OF THESE PARAMETERS IN MALIGNANT-TISSUE OF LUNG-CANCER PATIENTS

We studied the selenium (Se) concentration in whole blood and plasma, glutathione peroxidase (GSH-Px) activity in red blood cells and plasma , as well as both of these parameters in cancerous and tumor-free lung tissue of lung cancer patients. Blood samples were taken from 84 canc er patients and 61 healthy controls. Normal and neoplastic lung tissue s were obtained from 57 patients at the time of surgery. Se concentrat ions in whole blood and palsma were lower by 23% (p < 0.001) in patien ts compared with controls. GSH-Px activity in red cells was lower by 2 0.2% (p < 0.004) and in plasma by 11.7% (p < 0.05) in patients than in the control group. On the other hand, the tumor Se level was higher b y 66.6% (p < 0.0001) and GSH Pr activity by 49.5% (p < 0.0001) than in adjacent tumor-free tissue, No differences in Se concentrations and G SH-Px activities were found between squamous cell carcinoma anti adeno carcinoma nor among the clinical stages of the disease, In the whole b lood and plasma of cancer patients significantly lower Se concentratio ns were found in smokers than in nonsmokers. Significantly lower Se co ncentrations were also found among cancer patients who were smokers co mpared with controls. These findings show that in the blood of cancer the antioxidant ability, as measured by Se and GSH-Px, is reduced sign ificantly, The cause of increased Se and GSH-Px in the malignant part of the lung is not understood and requires further studies.