The ORs for GSTM1 null genotype were significant in female smokers (OR 3.03, 95% CI 1.09–8.40) and not in males (OR 1.42, 95% CI 0.53–4.06), which suggests that the effect of the GSTM1 null genotype on NSCLC is greater in female smokers than in male smokers with an equal smoking history [19]. The gene discussed is GSTM1; the disease is non-small cell lung carcinoma.