S100A9 and acute myeloid leukemia: In AML2 and AML3, the upregulated genes contained S100A8 and S100A9, which are known to be poor prognostic indicators in AML, and elevated expression of the heterodimer S100A8/S100A9 was previously reported to cause glucocorticoid resistance in MLL-rearranged infant acute lymphoid leukaemia cells [41] (Fig. 4e and Supplementary Fig. 8).