This is a multinational, multicenter, prospective and retrospective, observational, cohort study of patients with myeloproliferative neoplasm.

This is a multinational, multicenter, prospective and retrospective, observational, cohort registry of patients with MPN. The registry mainly involves study centres in Asia including but not limited to Hong Kong, Singapore, Malaysia, Taiwan, Korea and Thailand. Clinicopathologic characteristics, cytogenetic characteristics, mutational characteristics, treatment characteristics, outcomes and survivals of Asian patients MPN diagnosed between 2010-2025 will be collected to establish clinical registry.

Data on the clinicopathologic characteristics, cytogenetics, mutational profile, prognostic scoring treatment characteristics, responses to treatment, outcome and survivals will be collected through routine clinic visits and/or reviewing medical records. Data will be collected at diagnosis, and approximately every 6 months thereafter (for prospective data) and at progression until death/study termination.

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

Three study cohorts will be involved in the study. They are:

Prospective cohort - Subjects will be enrolled in the study at their diagnosis of MPN. All data will be collected on-study prospectively.

Partial prospective/retrospective cohort (partial-P/R) - Subjects will be enrolled in the study after they have been diagnosed of MPN for a period of time and still being followed up clinically (alive). Data from study enrollment forward will be collected prospectively at around 6-month intervals on-study. Data prior to study enrollment are the events of interest happened and will be collected retrospectively.

Retrospective cohort - Subjects enrolled in the study after they were diagnosed of MPN and died/lost to follow. All data will be collected retrospectively.