Diagnosis guide · Myeloproliferative neoplasms
Myeloproliferative neoplasms (MPNs)
If you or someone you love has just heard this diagnosis, start here. It covers several subtypes, and this guide shows how they differ, so you can find the one on your report.
Myeloproliferative neoplasms (MPNs) are a group of blood cancers in which the bone marrow makes too many red blood cells, white blood cells or platelets. The type depends mainly on which cells are overproduced. Examples are polycythemia vera (red cells), essential thrombocythemia (platelets), and chronic myeloid leukemia and chronic neutrophilic leukemia (white cells). In primary myelofibrosis, abnormal blood cells and fibers build up in the marrow. MPNs usually get worse slowly, and treatment ranges from watchful waiting and removing blood to medicines. Polycythemia vera, essential thrombocythemia and chronic-phase CML are usually treated without a transplant. A donor stem cell transplant is considered mainly for selected people with myelofibrosis, for disease that has turned into a more advanced form, such as advanced CML or leukemia, and for some people with chronic neutrophilic leukemia. The World Health Organization also classes juvenile myelomonocytic leukemia (JMML), a rare cancer of young children, as an MPN, and most children with it need a donor transplant.
In short
- Myeloproliferative neoplasms (MPNs) are blood cancers in which the bone marrow makes too many blood cells. These can be red cells, white cells or platelets.
- The type depends on which cells the marrow overproduces. Treatment ranges from watchful waiting and blood removal to medicines that lower counts or ease symptoms.
- Polycythemia vera, essential thrombocythemia and chronic-phase CML are usually treated without a transplant. A donor transplant is mainly for selected people with myelofibrosis or more advanced disease.
8 subtypes
Find the subtype on your report
The exact diagnosis shapes the treatment options. Your care team can explain the name on your report.
Polycythemia vera (PV)
Polycythemia vera (PV) is a slow-growing blood cancer, one of the myeloproliferative neoplasms, in which the bone marrow makes too many red blood cells and may make too many white cells and platelets as well. Almost everyone with PV has a JAK2 gene change. The thicker blood raises the risk of clots, and over many years PV can change into myelofibrosis or acute myeloid leukemia.
Not treated with transplantEssential thrombocythemia (ET)
Essential thrombocythemia (ET) is a slow-growing blood cancer, one of the myeloproliferative neoplasms, in which the bone marrow makes too many platelets. Most people have a JAK2, CALR or MPL gene change. The main risks are blood clots and bleeding, and over many years a small number of people see ET change into myelofibrosis or, less often, acute myeloid leukemia.
Not treated with transplantPrimary myelofibrosis (PMF)
Primary myelofibrosis is a blood-forming stem cell cancer that disrupts marrow function and can cause marrow scarring. Blood production may shift to the spleen and liver, leading to enlarged organs and symptoms.
Donor transplant optionPost-polycythemia vera myelofibrosis (post-PV MF)
Post-polycythemia vera myelofibrosis is progression of previously established polycythemia vera (PV) to a fibrotic marrow disorder. Blood production and symptoms change; anemia and an enlarged spleen may develop after the earlier phase of excess red cells.
Donor transplant optionPost-essential thrombocythemia myelofibrosis (post-ET MF)
Post-essential thrombocythemia myelofibrosis is progression of a previously established essential thrombocythemia (ET) to a fibrotic marrow disorder. Anemia, an enlarged spleen and other changes can replace the earlier pattern of mainly raised platelets.
Donor transplant optionChronic myeloid leukemia (CML)
Chronic myeloid leukemia (CML) is a blood cancer driven by the BCR::ABL1 fusion. Most people start with a targeted medicine, while a donor stem cell transplant remains an option for resistant disease or progression.
Limited transplant roleChronic neutrophilic leukemia (CNL)
Chronic neutrophilic leukemia (CNL) is a rare blood cancer in which the marrow makes too many mature neutrophils. It commonly involves a CSF3R gene alteration and must be distinguished from infection-related neutrophilia and other myeloid cancers.
Donor transplant optionJuvenile myelomonocytic leukemia (JMML)
Juvenile myelomonocytic leukemia (JMML) is a rare blood cancer of early childhood driven by abnormal RAS-pathway signaling. Most children need a donor stem cell transplant, while a small genetically defined group may follow a different course.
Donor transplant option
Also in this group
More myeloproliferative neoplasms explained in the library.
Advanced systemic mastocytosis (AdvSM)
Advanced systemic mastocytosis is a rare blood cancer in which abnormal mast cells, usually carrying the KIT D816V gene change, build up in the bone marrow and other organs and impair how they work. It includes aggressive systemic mastocytosis, systemic mastocytosis with an associated hematologic neoplasm, and mast cell leukemia.
Limited transplant roleMyeloid/lymphoid neoplasm with FGFR1 rearrangement
Myeloid/lymphoid neoplasm with FGFR1 rearrangement is a rare, aggressive blood cancer caused by a broken and rejoined FGFR1 gene on chromosome 8 (8p11). It can appear as a myeloproliferative neoplasm, an acute leukemia or a lymphoma, often with extra eosinophils. It used to be called 8p11 myeloproliferative syndrome.
Donor transplant option
Nearby
Related diagnosis guides
What to know
Key facts
- Types
- 8 MPN types, including CML, PV, ET and primary myelofibrosisWorld Health Organization classification, 5th edition (2022), as summarized by Khoury et al. in Leukemia (2022). Source: Types
- How it is often found
- Sometimes on a routine blood test, before any symptomsNCI patient summary on MPNs (updated May 2025), for PV, ET and primary myelofibrosis, which often cause no early signs. Source: How it is often found
- Most common gene change in PV
- JAK2, found in nearly everyone with PVMedlinePlus Genetics, U.S. National Library of Medicine (last updated July 2013). Source: Most common gene change in PV
- The only treatment that may cure it
- A donor stem cell transplant, for selected peopleEBMT 2025 practice recommendations (Europe). PV and ET are not transplant reasons unless they change into myelofibrosis, MDS or leukemia. Source: The only treatment that may cure it
How MPNs are diagnosed
MPNs often cause no symptoms at first. NCI notes that polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis may be found during a routine blood test. The test may show too many red cells, platelets or white cells.
Doctors then look for the cause. A complete blood count with differential and a blood smear show the numbers and look of each kind of blood cell. Gene tests on blood or marrow look for changes in the JAK2, CALR and MPL genes. Nearly everyone with PV has a JAK2 change. For PV, a blood test for erythropoietin (EPO), a hormone that tells the marrow to make red cells, is also used.
A bone marrow aspiration and biopsy is often part of the workup. A pathologist looks at the marrow under a microscope for abnormal cells. In myelofibrosis, the marrow fills with thick, scar-like fibers. Chromosome tests on marrow or blood cells can find other changes. One is the Philadelphia chromosome. It creates the BCR::ABL1 gene, which most people with chronic myeloid leukemia (CML) have.
Naming the exact MPN matters because the risks and the treatments differ. In PV, for example, the extra blood cells can make clots form, which raises the risk of a stroke or heart attack.
When transplant specialists are usually consulted
For myelofibrosis, U.S. guidelines from NMDP and ASTCT advise tissue typing (high-resolution HLA typing) and a transplant consultation at diagnosis for many people. This includes people with an intermediate-1 or higher DIPSS risk score, low blood counts or a younger age. It also includes people with high-risk gene changes, such as ASXL1 or TP53, or with no JAK2, CALR or MPL change. It also includes people whose JAK inhibitor medicine has stopped working. For CML, the guidelines point to a consultation when TKI medicines do not work well enough or cause too many side effects, or when the disease advances. European EBMT recommendations add that PV and ET are not reasons for a donor transplant unless they have changed into myelofibrosis, MDS or leukemia.
Read the guidanceLooking ahead
Outlook for MPNs
Many people live for years with an MPN. Researchers behind a large 2026 Swedish study describe the outlook as generally good. But they also found that life expectancy was lower than in the general population for every MPN type they studied.
The biggest difference is between types. In that study, the years lost in the first 15 years after diagnosis were fewest for ET, a bit more for PV and most for primary myelofibrosis. For primary myelofibrosis, NCI lists several factors that affect the outlook. They include age, the number of abnormal blood cells, the number of immature cells (blasts) in the blood, and chromosome changes. Fever, night sweats or weight loss matter too.
An MPN can change over time. NCI notes that MPNs sometimes become acute leukemia. European EBMT recommendations describe PV and ET changing into myelofibrosis, MDS or leukemia. CML is a special case. With daily targeted pills (TKIs), NCI says survival is expected to come close to normal life expectancy for most people.
About these numbers. Each one says which group of people it comes from, and the place and years where the source gives them. It describes what happened across that group, not what will happen to any one person. And a figure measured among people who had a transplant is not the same as the number of people who need one.
- 4.3 yearsAverage loss of life expectancy, all MPNs studied
Estimated for people aged 50 and older diagnosed with PV, ET, primary myelofibrosis or unclassifiable MPN in Sweden 2002–2021, compared with the general Swedish population; period analysis 2012–2021 (Haematologica, 2026). CML was not included.
Read the source: Average loss of life expectancy, all MPNs studied - ET 1.3; PV 1.8; primary myelofibrosis 4.4Years of life lost within 15 years of diagnosis, by type
Same Swedish study: people aged 50 and older diagnosed 2002–2021, period analysis 2012–2021, compared with the general population (Haematologica, 2026).
Read the source: Years of life lost within 15 years of diagnosis, by type
These are averages for large groups. They cannot tell any one person how long they will live.
Common questions
Is a myeloproliferative neoplasm a cancer?
Yes. MPNs are a group of blood cancers that start in the bone marrow. In an MPN, the marrow makes too many red cells, white cells or platelets. The World Health Organization's 2022 classification lists eight MPN types, including CML, polycythemia vera, essential thrombocythemia and primary myelofibrosis. Many people live for years with one. Researchers behind a large Swedish study describe the outlook as generally good, though life expectancy was lower on average than in the general population.
What is the life expectancy with an MPN?
It depends mostly on the type. A 2026 Swedish study of people aged 50 and older compared their life expectancy with that of the general population. The loss was smallest for ET, larger for PV and largest for primary myelofibrosis. The outlook section on this page gives the figures. These are group averages, not predictions.
Can an MPN turn into leukemia?
Sometimes. NCI says MPNs sometimes become acute leukemia, in which too many abnormal white blood cells are made. European EBMT recommendations also describe polycythemia vera and essential thrombocythemia changing into myelofibrosis or MDS (myelodysplastic syndrome). They say that once PV or ET has changed in one of these ways, a donor stem cell transplant may be considered.
Are MPNs hereditary?
Usually not. MedlinePlus Genetics explains that most cases of PV and ET are not inherited. The gene changes are acquired during a person's life and are found only in certain blood cells. In rare cases, PV runs in families. Less often, ET runs in a family too. Then it is inherited in an autosomal dominant pattern, which means one changed copy of the gene is enough to cause it.
Does an MPN need a bone marrow transplant?
Usually not. European EBMT recommendations call a donor stem cell transplant the only treatment that can cure an MPN. But they say PV and ET are not reasons for one unless they have turned into myelofibrosis, MDS or leukemia. For myelofibrosis, a transplant is considered for eligible people with higher-risk scores. For CML, U.S. guidelines point to a transplant consultation mainly when TKI medicines do not work well enough or the disease advances.
For your next appointment
Myeloproliferative neoplasms (MPNs)
From the Jada Bascom Foundation disease library, jadabascomfoundation.org. Printed .
Questions to bring to your care team
- Which MPN is it, and which gene change did the tests find?
- What is my risk of blood clots, and what are we doing to lower it?
- How will we watch for signs that it is changing into myelofibrosis or leukemia?
- If it is myelofibrosis, what is my risk score, and does it make sense to start HLA typing now?
- What is the goal of each treatment you are suggesting?
- What would make a transplant worth considering later on?
- Are there clinical trials that might fit?
- Where can our family find support during treatment?
A one-page list to take to the next appointment, with room for notes.
Supporting someone with a diagnosisSupport for patients and families
These independent organizations offer information and support. JBF is not affiliated with them.
- MPN Research Foundation A US nonprofit that funds MPN research and offers patients and caregivers disease information, clinical trial resources, a patient registry and personal stories.United States
- MPN Voice A UK charity offering information, a buddy program, patient forums and well-being advice to people with MPNs and their families.United Kingdom
- MPN Advocacy & Education International A nonprofit running education programs, support groups and advocacy for people with myelofibrosis, polycythemia vera and essential thrombocythemia, in the US and abroad.United States and international
Ways to help
Help another family understand.
Most people with myeloproliferative neoplasms (MPNs) are treated without a registry donor. A clear explanation can help the next family who hears this diagnosis, and many people with other blood cancers and blood disorders need a donor who is a stranger.
Learn and share
Most families meet these words for the first time at a diagnosis. Passing on a plain, sourced explanation is a real help.
Support this work
Gifts to the Jada Bascom Foundation support donor-awareness education like this page, community outreach, drive planning and referrals to official registries.
Join the registry
JBF points you to the official registry that serves your country. It explains who can join and what donation involves.
Keep learning
Understanding transplant
Short explainers on what a transplant is and what it means for a family.
Sources and further reading
- Myeloproliferative Neoplasms Treatment (PDQ), Patient Version
National Cancer Institute, 2025-05-12 - Indications for haematopoietic cell transplantation and CAR-T for haematological diseases, solid tumours and immune disorders: 2025 EBMT practice recommendations
EBMT / Bone Marrow Transplantation, 2025-09-09 - The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Myeloid and Histiocytic/Dendritic Neoplasms
WHO classification authors, Leukemia, 2022-06-22 - Juvenile Myelomonocytic Leukemia Treatment (PDQ), Health Professional Version
National Cancer Institute, Updated 2024-12-10; accessed 2026-09-26 - Loss of life expectancy in patients with myeloproliferative neoplasms in Sweden
Haematologica (Leontyeva et al.), 2026-03 - Polycythemia vera
MedlinePlus Genetics, US National Library of Medicine, 2013-07-01 - Essential thrombocythemia
MedlinePlus Genetics, US National Library of Medicine, 2014-09-01 - Chronic Myeloid Leukemia Treatment (PDQ), Patient Version
National Cancer Institute, 2025-04-09 - Chronic Myeloid Leukemia Treatment (PDQ), Health Professional Version
National Cancer Institute, 2025-03-13 - Recommended timing for transplant consultation: Myeloproliferative neoplasms (MPN) and myelofibrosis (MF)
NMDP and ASTCT, Accessed 2026-09-26 - Recommended timing for transplant consultation: Chronic myeloid leukemia (CML)
NMDP and ASTCT, Accessed 2026-09-26
