Although originally defined as a tumor suppressor gene (23, 24), accumulating evidence suggests that WT1 has an oncogenic role in leukemogenesis and tumorigenesis (25), as inhibition of WT1 gene expression resulted in suppression of leukemia growth in vitro, whereas its forced expression resulted in leukemia induction in mice (26, 27). The gene discussed is WT1; the disease is leukemia.