Inclusion Criteria:

For the 110 patients with MPN:

• - Patients with PV, ET or PMF.

• - DNA extracted from purified granulocytes at time of diagnosis.

• - No treatment likely to impact DNA methylation (chemotherapy, immunosuppressants in particular) For the 10 subjects without MPN: - Absence of hematological malignancy.

• - Search for JAK2V617F mutation in the context of reactive thrombocytosis or secondary polycythemia.

• - Absence of treatment likely to impact DNA methylation (chemotherapy, immunosuppressants in particular)

  Exclusion Criteria:

  For the 110 patients with MPN: - Patients without PV, ET or PMF.

• - Patients without purified granulocytes DNA available at time of diagnosis.

• - Patients treated by cytoreductive drug, demethylating agent, chemotherapy or immunosuppressive therapy at the time of DNA sampling.

• - Patients with less than 2 years' follow-up.

For the 10 subjects in NMP :

• - Patients with hematological malignancy and/or solid cancer.

- Patients treated by cytoreductive drug, demethylating agent, chemotherapy or immunosuppressive therapy at the time of DNA sampling

Myeloproliferative Neoplasia (MPN) are hematological malignancies characterized by the excessive production of myeloid cells. They include Essential Thrombocythemia (ET), Polycythemia Vera (VP) and Primary Myelofibrosis (PMF). Thrombosis are the most frequent complications and are largely responsible for the morbidity and mortality observed in ET and PV patients. The most feared complications are hematological transformations (into myelofibrosis for PV and ET, into acute myeloid leukemia for PV, ET and PMF). The prognostic assessment of MPN patients is mainly based on clinical data. Although recent studies have shown that certain mutations are associated with a poorer prognosis, age remains the main risk factor affecting survival in MPN patients. Recent studies have shown that DNA methylation can be used to determine an "epigenetic age". Interestingly, this epigenetic age is associated with the development of cardiovascular disease and cancer. In this project, the epigenetic age of MPN patients will be determined by studying the DNA methylation at diagnosis using the Infinium Human MethylationEPIC kit (Illumina). Epigenetic age will be determined with the most commonly used epigenetic clocks (DNAmAge, DNAmHannum, DNAmPhenoAge, DNAmSkinClock, DNAmGrimAge, intrinsic epigenetic age acceleration, extrinsic epigenetic age acceleration). It will be searched for an association between accelerated epigenetic aging (as assessed by the difference between epigenetic age and chronological age) and the type of MPN, the clinical and biological presentation at diagnosis (including the mutational profile of patients) and the occurrence of thrombosis and hematological evolution into myelofibrosis and/or acute leukemia.

Arms

: Patients with ET

45 patients with ET: 15 without thrombotic event (neither at diagnosis nor during follow-up) 15 with thrombotic events (thrombosis at diagnosis or within 2 years of diagnosis) 15 who progressed to myelofibrosis or AML during follow-up

: Patients with PV

45 patients with PV 15 without thrombotic event (neither at diagnosis nor during follow-up) 15 with thrombotic event (thrombosis at diagnosis or within 2 years of diagnosis) 15 who progressed to myelofibrosis or AML during follow-up

: Patients with PMF

20 patients with PMF: 10 without transformation into AML 10 patients who progressed to AML

: Patients without MPN

10 patients without MPN

Interventions

Biological: - Assessment of the epigenetic age

Retrospective assessment of the epigenetic age on DNA samples obtained at diagnosis