Radon, secondhand smoke, glutathione-S-transferase M1 and lung cancer among women

December 12th, 2017

Tobacco smoke and ionizing radiation induce oxidative stress by transmitting or generating reactive oxygen species (ROS). We hypothesized that glutathione-S-transferase M1 (GSTM1) null homozygotes would have decreased ability to neutralize ROS that might increase their susceptibility to lung cancer.A case-only design was used with lung cancer cases pooled from 3 previously completed case-control studies using archival tissue samples from 270 lung cancer cases to genotype GSTM1. Radon concentrations were measured with long-term a-track radon detectors. Secondhand smoke (SHS) was measured with questionnaires and interviews. Unconditional logistic regression was used to calculate the interaction odds ratios (OR) and 95% confidence intervals (95% CI). Radon concentrations >121 Bq m23 were associated with a >3-fold interaction OR (OR 5 3.41; 95% CI 5 1.10, 10.61) for GSTM1 null homozygotes compared to GSTM1 carriers; the linear trend was significant (p trend 5 0.03). The SHS and GSTM1 interaction OR was also elevated (OR 5 2.28; 95% CI 5 1.15–4.51) among never-smokers. This may be the first study to provide evidence of a GSTM1 and radon interaction in risk of lung cancer.Additionally, these findings support the hypothesis that radon and SHS promote neoplasia through shared elements of a common pathway.