Glutathione S-transferase M1 genotypes and the risk of vulvar cancer: A population-based case-control study

Glutathione S-transferases (GSTs) facilitate the excretion of a variety of potential carcinogens. Some 50-60% of Caucasians are homozygous for the nul l allele of GSTM1, a gene responsible for the presence of one of these enzy mes. The authors examined whether women with the GSTM1 null genotype are at altered risk of vulvar cancer. They obtained peripheral blood specimens fr om 18 to 79-year-old residents of King, Pierce, and Snohomish counties of w estern Washington who were diagnosed with vulvar cancer between April 1991 and June 1994, Blood specimens were also obtained from controls identified via random digit telephone dialing of western Washington households. The au thors determined the GSTM1 genotype of 137 cases (120 in situ and 17 invasi ve cases) and 248 controls. The frequency of the GSTM1 null genotype was 46 .7% among cases and 57.3% among controls. The age-adjusted odds ratio assoc iated with the GSTM1 null genotype was 0.7 (95% confidence interval: 0.4, 1 .0). Among current smokers of cigarettes, the age-adjusted odds ratio assoc iated with the GSTM1 null genotype was 0.5 (95% confidence interval: 0.2, 0 .9), differing little between heavy and light smokers. Our data suggest tha t women with the GSTM1 null genotype are not at increased risk of vulvar ca ncer.