To investigate this in more detail, we screened the subgroups of patients by looking at the expression of typical myeloid genes that are known MYB targets; we found marked differences in the expression of several genes that are normally either positively (e.g. BCL2, CDK6, FLT3, GFI1 and KIT and MEIS2) or negatively regulated (such as BCL6, CD14, DUSP6, ITGAM, S100A8 and S100A9) by MYB, in MLL-rearranged leukaemia patients, while only minimal differences were observed for the same genes in the complex karyotype subgroup when comparing MYB-high versus MYB-low subgroups (Fig. 3D). Here, S100A9 is linked to leukemia.