[Molecular mechanisms in myeloproliferative diseases and myelodysplastic syndromes]

Little was known about the mechanisms for myeloproliferative diseases (MPD) until 2005 when an activating mutation in the JAK2 tyrosine kinase (JAK2 V617F) was identified in >95% of patients with polycythemia vera (PV), and in a significant proportion of patients with essential thormbocythemia (ET) and primary myelofibrosis (PMF). Furthermore, activating abnormalities of some tyrosine kinases were identified in MPD and related diseases, suggesting that constitutive activation of the signaling pathway is a unifying feature of these diseases. On the other hand, the molecular mechanism of myelodysplastic syndromes (MDS) is still poorly understood. Recent study revealed that two types of AML1/RUNX1 mutants function via distinct molecular mechanisms to produce mutant-specific phenotypes of MDS. The mechanisms of MPD and MDS gradually become clear.