Myeloproliferative neoplasms (MPN) are clonal hematopoietic disorders sharing a common natural evolution: a chronic phase, characterized by a major risk of vascular events, followed by an accelerated phase eventually leading to transformation to acute leukemia. MPN include polycythemia vera, essential thrombocythemia, primary myelofibrosis, and rarer entities. During the past years, CML became a paradigm for targeted therapy and personalized cancer medicine. For other MPNs, the discovery of the JAK2V617F mutation followed by many other mutations, opened similar perspectives. However, several questions remain to be answered in MPNs regarding the clinical implication of these major scientific discoveries: what is the clinical impact of JAK2V617F and other molecular biomarkers on the risks of complications and progression? Can these new biomarkers be used in the perspective of a personalized therapy of MPNs? his project will focus on the qualification of a series of known mutations as biomarkers in MPNs based on large multicenter cohorts of patients with well-annotated samples