Rationale: Patients with deletions in GSTM1 which affect Phase II detoxification processes have been shown to have reduced levels of DNA adducts [16], and increased levels of GSTA1 circulating activity [17], when adequate levels of cruciferous vegetables have been consumed. Risk for lung cancer drops by up to 80% in individuals lacking GSTM1 and/or GSTT1 genes when consumption of cruciferous vegetables is high [18]. The gene discussed is GSTM1; the disease is lung cancer.