SF3B1 and myelodysplastic syndrome: In all relevant studies published to date, RNA-Seq has been performed on unfractionated bone marrow mononuclear cells from a small number of MDS patients with SF3B1 mutations (n⩽3 per study), revealing interesting data.11, 37, 38 MDS arise in the HSC, and it is thus of critical importance that the effects of SF3B1 mutation on the transcriptome are studied in the cell of origin.