Some attractive results were acquired; we showed a proportion of CML cancer attributable to interaction between smoking and GSTM1 null, GSTT1 null, and GSTP1M*genotypes around 42%, 39%, and 13% respectively, furthermore, the relative excess risk due to interaction was 2.75, 1.26, and 0.58 for GSTM1 null, GSTT1 null, and GSTP1M* genotypes, respectively. The gene discussed is GSTM1; the disease is cancer.