Oxidant stress and glioblastoma multiforme risk: Serum antioxidants, gamma-glutamyl transpeptidase, and ferritin

Case-control studies of serum antioxidants are difficult to interpret, beca use antioxidants may be altered by the disease under study. However, becaus e glioblastoma multiforme (GBM) is a relatively rare disease, a cohort stud y would require a large sample observed for many years. In the present case -control pilot study (34 cases and 35 controls), we evaluated the associati on between,serum levels of ascorbic acid (AA) and alpha and gamma -tocopher ol (alpha -T and gamma -T) measured before diagnostic surgery. To control f or influence of GEM on serum AA, alpha -T, and gamma -T we adjusted for oxi dant stress indexes (gamma -glutamyl transpeptidase and uric acid) and an a cute-phase response index (serum ferritin). When adjusted AA is inversely r elated to GEM (p for trend = 0.007). In addition, AA interacts with alpha - T to further reduce GBM risk (test for interaction, p = 0.04). gamma -T is not associated with GEM (p = 0.71). However, gamma -glutamyl transpeptidase (p = 0.004), coenzyme Q (p = 0.01), and ferritin (p = 0. 009) are positive ly and uric acid (p = 0.000) is negatively related to GEM; We conclude that 1) AA and alpha -T are jointly related to GEM after adjustment for GBM-pro duced oxidant stress and 2) there is a strong association between the prese nce of GEM and oxidant stress.