NUP98-HOXA9 [t(7;11) (p15;p15)] is associated with inferior prognosis in de novo and treatment-related acute myeloid leukaemia (AML) and contributes to blast crisis in chronic myeloid leukaemia (CML).
As a possible explanation for the decreased levels of Numb in the blast crisis phase, we show that NUP98-HOXA9, an oncogene associated with blast crisis CML, can trigger expression of the RNA-binding protein Musashi2 (Msi2), which in turn represses Numb.
Interestingly, a patient with poorer prognosis (high Sokal's score), showing the highest HOXA9/ABL ratio, quickly entered a blast crisis and died 5 months later.
Reverse transcriptase polymerase chain reaction identified the NUP98/HOXA9 transcript, suggesting that the NUP98/HOXA9 fusion protein could play a critical role in the progression to blast crisis.