GSTM1 and leukemia: Of these, there were 104 studies from 86 publications (14,100 leukemia cases and 23,793 controls, Table 1, Supplementary Table S1) for the GSTM1 null genotype, 94 studies from 79 publications (12,928 leukemia cases and 22,036 controls, Table 2, Supplementary Table S1) for the GSTT1 null genotype, and 33 studies from 30 publications (4,613 leukemia cases and 6,826 controls, Supplementary Table S1) for the combined effects of the GSTM1 present/null and GSTT1 present/null polymorphisms.