Glutathione peroxidase, glutathione reductase and protein oxidation in patients with glioblastoma multiforme and transitional meningioma.

Purpose: The aim of this study was to assess glutathione peroxidase (GPx), glutathione reductase (GRx) and protein oxidation (POx) levels in patients with glioblastoma multiforme (GBM) and transitional meningioma (TM) and to compare with normal brain tissues.

Methods: GPx, GRx and POx levels were measured in 48 brain tumors obtained during surgery and 15 normal brain tissues that were collected during autopsy. Results were compared between two groups.

Results: GPx and GRx activities were significantly lower in GBM and TM when compared to controls and the difference was statistically significant (P = 0.0001). Furthermore, the decrease in enzyme activities was more evident in GBM than in TM. In contrast, POx levels were found to be higher in both GBM and TM compared to controls and showed statistically significant difference (P = 0.00001). Increase in POx levels was clearer in GBM than TM.

Conclusions: GPx and GRx decreased and POx increased significantly in both GBM and TM when compared to normal brain tissues. Further, clinical studies with a larger patient population are required to show the role(s) of antioxidant enzymes in brain tumors more accurately.