S100A9 mainly characterizes M-MDSCs and together with its binding partner, S100A8, is included in the DAMP molecules displaying intra- and extracellular functions and inflammatory, antiinflammatory and immune regulatory properties.29,30 Varying S100A9 expression resulted in different MDSC functions, with more proinflammatory effect in low risk and immunosuppressive effect in high-risk MDS. This evidence concerns the gene S100A9 and myelodysplastic syndrome.