We next evaluated the contribution of STAT5 in the regulation of catalase and Glrx1 protein expression and found that RNA interference-mediated knockdown of STAT5 in Bcr-Abl+ leukemia cells increased the expression of catalase and Glrx1 (2 to 3 fold) (Figure 3D and Supplementary Figure S3A). This evidence concerns the gene STAT5A and leukemia.