Nitric oxide levels and lipid peroxidation in plasma of patients with gastric cancer.

BACKGROUND The aim was to investigate the levels of malondialdehyde and total NO(2)(-) plus NO(3)(-) marker for NO(*) generation in gastric carcinoma and to correlate their levels with the cancer stage. METHOD The pretreatment plasma samples were obtained from 38 patients with gastric cancer (seven patients at stage II, 19 at stage III and 12 at stage IV). Nitrite (NO(2)(-)) and nitrate (NO(3)(-)) levels, the end products of nitric oxide (NO(*)), were determined in these samples. NO(2)(-) was measured by using the Griess reaction and after enzymatic conversion of NO(3)(-) into NO(2)(-) by nitrate reductase, the resultant NO(2)(-) was also measured by the same method. Malondialdehyde (MDA), a lipid peroxidation marker, was measured by the thiobarbituric acid method. RESULTS The levels of plasma MDA, NO(*) and NO(3)(-) were significantly higher in patients with gastric cancer compared with the healthy control group. Higher levels of MDA, NO(*) and NO(3)(-) were observed as the stage of the disease increased. CONCLUSION We found that increased NO(*) production and MDA levels were present in plasma of patients with gastric cancer. These increases can be associated with the oxidant-antioxidant status in these patients.