WT1 has been largely reported to be overexpressed in all types of leukemias both of myeloid and lymphoid origins, as well as during blast crisis of chronic myeloid leukemia, and increased WT1 levels are associated with poor outcomes because of higher incidence of relapse and resistance to standard chemotherapy [11,14,16,17]. This evidence concerns the gene WT1 and chronic myelogenous leukemia, BCR-ABL1 positive.