Flying too close to the sun: loss of IKAROS accelerates CML

Chronic phase-chronic myeloid leukaemia (CP-CML) can progress via an 'accelerated phase' (AP) to acute leukaemia (blast crisis; BC). A new study found that IKAROS, a tumour suppressor involved in B-cell acute lymphoblastic leukaemia, was usually underexpressed or absent in bone-marrow blasts during the AP or BC, compared with CP-CML cells. Expression of dominant negative IKAROS conferred an accelerated-phase phenotype to CD34⁺ CP-CML cells in vitro and in a mouse xenograft model. Thus, loss of IKAROS is implicated in CP-CML progression and has potential diagnostic application.