The C3435T Polymorphism of MDR1 and Susceptibility to Adult Glioma

Abstract

Introduction: The multidrug resistance-1 (MDR1) gene encodes a pump that prevents potentially carcinogenic substances from crossing the blood-brain barrier. We compare adult glioma cases and controls for the C3435T polymorphism that has been associated with reduced MDR1 expression. Methods: Adult glioma in the San Francisco Bay area and population-based controls were identified between 1991–1994 and 1997–1999. Genotyped cases (n = 458) and controls (n = 528) were compared using logistic regression controlling for age, gender and ethnicity, with later stratification by ethnicity, gender and histology. Results: With CC as the referent, the TT genotype was nonsignificantly less frequent among cases compared to controls (OR, 0.87; 95% CI: 0.6, 1.2). After stratification, only male glioblastoma was associated with TT genotype (OR, 0.51; 95% CI: 0.3, 1.0). Conclusions: Although the C3435T polymorphism does not appear to be associated with other types of glioma, we cannot rule out that this MDR1 polymorphism may be associated with glioblastoma among men.