The predictive role of Paraoxonase 1 (PON1) activity on survival in patients with metastatic and nonmetastatic gastric cancer.

Oxidative stress is known to be implicated in the pathogenesis of malignancies including gastric cancer (GC). Paraoxonase 1(PON1) is a member of antioxidant defense system which acts by hydrolysing peroxidases. Our aim is to assess the levels PON1 activity in different stages and localizations of GC and analyze the predictive role of PON1 activity on overall survival in GC.One hundred and twenty six patients with GC were enrolled to the study. Patients were divided into two groups; group I (nonmetastatic GC, n=65) and group II (metastatic GC, n=61). Paraoxonase 1 activity, albumine and lactate dehidrogenase levels and whole blood count were analyzed. Union Internationale Contre le Cancer system was used for staging procedure.Patients at advanced N or M stage have significantly lower levels of PON1 (34.26 U/L and 29.88 U/L, p=0.04 and p=0.03; respectively). Gender, Lauren's classification, grade, localization and T stage of tumor have nonsignificant impact on PON1 activity. PON1 activity was a significant prognostic factor in GC as well as metastasis, localization of tumor and low hemoglobine or albumine level.Lower levels of paraoxonase 1 activity in patients with metastatic gastric cancer may reflect the presence of enhanced oxidative stress in advanced stages of the disease. PON1 activity is a significant and independent predictor of overall survival. Identifying novel prognostic markers can help to establish appropriate therapeutic strategies, to determine preventive measures and to improve survival rates.