This could be due to the observation that JAK2/IDH-mutant disease remains an accelerated-phase MPN versus the AML observed in combined Flt3ITD- and Tet2/Idh2-mutant disease, such that the leukemic stem cell remains in the LT-HSC compartment in chronic-phase disease until blast transformation. Here, IDH2 is linked to acute myeloid leukemia.