GSTM1-null had significant associations with cancer risks (for smokers: OR = 1.347, 95% CI: 1.196–1.516, P < .001; for nonsmokers: OR = 1.423, 95% CI: 1.270–1.594, P < .001; for drinkers: OR = 1.748, 95% CI: 1.093–2.797, P = .02). This evidence concerns the gene GSTM1 and cancer.