All patients diagnosed or followed in Brest University Hospital for Philadelphia negative myeloproliferative neoplasms will be included in this observational study.

Myeloproliferative neoplasms recorded included: polycythemia vera, essential Thrombocythemia and Primary Myelofibrosis.

This is a not interventional study. Alive patients need to sign a non-opposition consent form.

Patients will be followed until last news (death, change of reference centre...).

In this retrospective and prospective study, clinical and biological data from diagnosis until last news will be recorded.

Clinical data collected: patients and disease characteristics at the time of the diagnosis, disease and mutational status, cardio-vascular risk factors, history of thrombosis and cancer.

Biological data collected: hemogram and bone marrow results if available. During the follow-up new data will be noted: treatment changes (reasons of change and type of drug), thrombotic events (localization, date and hemogram), phenotypic evolutions (type and date), death (date and etiology).

Inclusion Criteria:

• Patients with essentiel thrombocythemia, polycythemia vera or primary myelofibrosis
• Signature of the non-opposition consent form

Exclusion Criteria:

• None

Patients followed for essentiel thrombocythemia, polycythemia vera or primary myelofibrosis