POPULATION-BASED STUDY OF GLUTATHIONE-S-TRANSFERASE-MU GENE DELETION IN ADULT GLIOMA CASES AND CONTROLS

Gene deletion at the glutathione S-transferase mu locus (GSTM1) has pr eviously been associated with increased risk for environmentally-induc ed cancers (e.g. smoking-related lung cancer), In the present study we examined the hypothesis that GSTM1 deletion is a risk factor for mali gnant brain tumors in adults, We compared the prevalence of the GSTM1 homozygous deletion polymorphism in 158 Caucasian adults with gliomas with 157 controls, Cases and controls were drawn from a large populati on-based case-control study of brain cancers in six San Francisco Bay area counties, Overall, the prevalence of the GSTM1 deletion was simil ar in cases (83/158; 53%) and controls (78/157; 50%), Among brain tumo r cases, analysis of variance modeling indicated a significant interac tion of GSTM1 genotype and gender associated with age at diagnosis (P = 0.02), This effect was due to the fact that women with GSTM1 deletio n were younger on average at diagnosis than women who were GSTM1 posit ive (43.9 years versus 52.4 years, respectively), Age at diagnosis amo ng men was similar for those who were GSTM1 deleted and GSTM1 positive (49.4 years and 47.2 years, respectively), The younger age at diagnos is of GSTM1 null female cases compared with GSTM1 positive cases was o bserved in astrocytoma as well as the higher grade tumors (e.g. gliobl astoma multiforme), There was no association of GSTM1 deletion with ag e or gender in controls, These studies suggest that among female cases , GSTM1 deletion may be associated with earlier age at onset, Confirma tion of these findings could provide important clues to gene-environme nt interactions in the etiology of malignant brain tumors.