Asian Myeloproliferative Neoplasm (MPN) Registry

Inclusion Criteria: 1. Age ≥ 18 years old at the time of diagnosis of MPN. 2. Subject was diagnosed with one of the following disorders according to the 2017 WHO classification (for patients diagnosed before 2017, the bone marrow reports will be re-evaluated according to the 2017 WHO classification): 1. Polycythaemia vera 2. Essential thrombocythemia 3. Primary myelofibrosis, pre-fibrotic/early stage 4. Primary myelofibrosis, overt fibrotic stage 5. Post-polycythaemia vera myelofibrosis 6. Post-essential thrombocythaemia myelofibrosis 7. MPN-unclassifiable 3. All subjects need to provide informed consent. Exclusion Criteria: A subject will not be eligible if he/she meets any of the following criteria: 1\. Subject was diagnosed with myelodysplastic syndrome, myelodysplastic syndrome/myeloproliferative neoplasm, or chronic myeloid leukaemia BCR-ABL1 positive, under the 2017 WHO classification