An analysis of a cohort of 16 PV patients with leukemic transformation showed that post-PV MF and accelerated phase disease was associated with JAK2 mutated AML while AML with WT JAK2 arose from chronic phase disease possibly as a consequence of genotoxic therapy and damage to non JAK2 mutated HSCs [18]. Here, JAK2 is linked to acute myeloid leukemia.