Over-expression of MSI2, but not HOXA9, emerged in two other cases of Ph + blast crisis (BC1 and BC2, Figure 2a and b) with additional cytogenetic rearrangements suggesting that, in addition to HOXA9 and HOXA13, alternative mechanisms may deregulate MSI2 in the presence of clonal evolution and acute phase progression of Ph + CML. The gene discussed is HOXA13; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.