In Myelodysplastic Syndrome (MDS), the expression of PD-1 in hematopoietic stem/progenitor cells and PD-L1 in MDSC are increased, and c-Myc is necessary for S100a9 to up-regulate PD-1/PD-L1 expression [46]. This evidence concerns the gene S100A9 and myelodysplastic syndrome.