S100A9 and acute myeloid leukemia: The minimal set of 13 genes (PRKAR1B, GNAI1, PRODH, CD52, KRT18, CLIP3, CLU, PTGDS, HOXB2, CLEC2B, CTSW, S100A9, and MYH11) was sufficient to distinguish one AML subtype from another on the basis of gene expression solely.