The loss of stem cell support observed in LR-MDS stroma contrasts with findings on HR-MDS by Jann et al.129, who identified a CXCL12–high expressing MSC subset (StemCAR) enriched in response to high-risk MDS blasts and diminished following hypomethylating agent therapy. This evidence concerns the gene CXCL12 and myelodysplastic syndrome.