Oxidant Stress and Glioblastoma Multiforme Risk: Serum Antioxidants, γ-Glutamyl Transpeptidase, and Ferritin

Abstract

Case-control studies of serum antioxidants are difficult to interpret, because antioxidants may be altered by the disease under study. However, because glioblastoma multiforme (GBM) is a relatively rare disease, a cohort study would require a large sample observed for many years. In the present case-control pilot study (34 cases and 35 controls), we evaluated the association between serum levels of ascorbic acid (AA) and α- and γ-tocopherol (α-T and γ-T) measured before diagnostic surgery. To control for influence of GBM on serum AA, α-T, and γ-T, we adjusted for oxidant stress indexes (γ-glutamyl transpeptidase and uric acid) and an acute-phase response index (serum ferritin). When adjusted, AA is inversely related to GBM (p for trend = 0.007). In addition, AA interacts with α-T to further reduce GBM risk (test for interaction, p = 0.04). γ-T is not associated with GBM (p = 0.71). However, γ-glutamyl transpeptidase (p = 0.004), coenzyme Q (p = 0.01), and ferritin (p = 0.009) are positively and uric acid (p = 0.000) is negatively related to GBM. We conclude that 1) AA and α-T are jointly related to GBM after adjustment for GBM-produced oxidant stress and 2) there is a strong association between the presence of GBM and oxidant stress.