IDH2 and myelodysplastic syndrome: (1) IDH mutations occur at low frequency (3.42%–12.27%) in MDS, but IDH1/2 mutations are more frequent in both de novo AML (7.5%–31%) and AML arising from MDS (7.5%) [15], [33], [34], [35], [36], [37], indicating a role for IDH mutations in leukemic transformation of MDS.