Recently we have shown that the restricted expression of the BCR-ABL oncogene, linked to chronic myeloid leukemia (CML) disease, to the hematopoietic stem cell compartment is capable of generating a full-blown tumour with all its differentiated cellular components, showing a hands-off role for BCR-ABL in regulating CML formation [7-12]. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.