Indeed, quantifying the in situ CXCL12 protein levels, an essential HSPC support and maintenance factor86, relative to the number of CD271+ stromal cells in BM biopsies from our cohort, revealed a significantly lower CXCL12/CD271 ratio in MDS compared to CHIP and Control (Fig. 4B, C). Here, CXCL12 is linked to myelodysplastic syndrome.