Background and Objectives: Gastric cancer is the most incident disease in Iran that leads to death. This study was designed to evaluate the oxidative and antioxidative status in patients with gastric cancer by detecting paraoxonase 1 and arylesterase activities together with the level of malondialdehyde. The purpose of the present investigation was determination of Paraoxonase /Arylesterase activity and malondialdehyde (MDA) levels in the serum of patients with Gastric cancer.

  Methods: In a case-control study, 20 subjects who diagnosed as gastric cancer individuals that referred to Ardabil Aras Clinic were selected from 2008 up to 2009. The case groups were matched with control group (30 subjects). Arylesterase and paraoxonase activities of paraoxonase-1 (PON-1), MDA levels and lipid profile were determined spectrophotometrically in serum of subjects.

  Results: Upon matching of case and control groups, paraoxonase and arylesterase activities in patients with gastric cancer showed to be significantly lower than healthy subjects (190 ± 68.95 IU/L vs 258 ± 68.59 IU/L, 30.5 ± 28.4 U/L vs 284.23 ± 163.2 U/L respectively, P ≤ 0.001). Standardized activities of paraoxonase and arylesterase of case group were lower than controls (P ≤ 0.001). MDA levels have revealed significant increasing in cases than controls. In present study, HDL cholesterol and triglyceride levels were found to decrease in patient sera too, but the levels of total cholesterol and LDL cholesterol didn’t show to be different between two groups.

  Conclusion: It was concluded that in patients with gastric cancer, oxidative stress was raised by attenuation of antioxidant system and oxidant levels rising.