Figures 5, 6 show the funnel plots of the nonparametric “trim and fill” method. We need to add 18 articles in the future for the GSTM1 present/null polymorphism with risk of leukemia (Figure 5). Moreover, we need to add eight studies for the combined effects of the GSTM1 present/null and GSTT1 present/null polymorphisms on the risk of leukemia (Figure 6). This evidence concerns the gene GSTM1 and leukemia.