Myeloproliferative Neoplasms (MPNs) 101

Myeloproliferative neoplasms (MPNs), also known as myeloproliferative disorders (MPDs), are a collection of blood cancer disorders that are believed to be caused by mutations in bone marrow stem cells. The mutations result in the production of too many of one or several different types of blood cells, which in turn thickens the blood and crowds the bone marrow.

In this article, we will take a look at the different types of myeloproliferative neoplasms, along with other commonly asked questions about MPN.

What is a Myeloproliferative Neoplasm?

Often the names of diseases can be more confusing than the disease itself. In the case of Myeloproliferative Neoplasms (MPN), even just spelling the disease can give you a headache.

While we’ve already defined MPNs as a group of diseases in which the bone marrow produces too many blood cells, breaking apart the name of the disease itself helps make it more approachable.

• Myelo – A combining form that means bone marrow.
• Proliferative – Comes from the verb proliferate meaning rapid production or increase in number.
• Neoplasm – An abnormal mass of tissue that forms when cells grow faster or in larger quantities than they should.

When you break down the name of the grouping of the diseases the types of diseases that fall under the grouping become easier to understand.

What are the Different Types of Myeloproliferative Neoplasms?

According to National Cancer Institute, there 6 different types of MPNs that are typically defined by the type of cell that they most significantly impact. They include:

• Chronic myelogenous leukemia (CML) – overproduction of myeloblasts, an immature cell that makes white blood cells called myeloid cells.
• Polycythemia vera – overproduction of red blood and other blood cells resulting in the thickening of the blood.
• Primary myelofibrosis – bone marrow replaces fibrous tissue and blood is produced in organs such as the liver and spleen.
• Essential thrombocythemia – overproduction of blood platelets (thrombocytes).
• Chronic neutrophilic leukemia – overproduction of neutrophils (a type of white blood cell).
• Chronic eosinophilic leukemia – too many eosinophils (a type of white blood cells) are found in bone marrow, blood, and other tissues.

While all of the above diseases are classified as myeloproliferative neoplasms, they each have their own symptoms and treatment plans.

Is MPN Cancer?

Yes, a Myeloproliferative Neoplasm is considered a form of blood cancer. However, MPN actually wasn’t considered a form of cancer until 2008 when the name changed from Myeloproliferative Disease and the World Health Organization reclassified them as cancers.

Who is at the Highest Risk for an MPN?

Myeloproliferative neoplasms have not been linked to family genetics. In fact, most people with MPN have no family history of the disease.

MPN is most commonly diagnosed in those over the age of 50. However, it can occur in younger people and very rarely in children.

What is the Cause of MPN?

The exact cause of Myeloproliferative Neoplasm is unknown. However, MPN has been linked with the mutation of the gene Janus kinase 2 (JAK2). While this linkage doesn’t give researchers an answer to what causes MPN, it does help guide future research and treatment plans.

According to Mount Sinai, there are two theories about the cause of MPN:

• Some patients, specifically those with CML, have an abnormally shortened Philadelphia chromosome.
• Overexposure to radiation, electrical wiring, and chemicals (specifically benzene and toluene) may cause an overproduction of blood cells.

While researchers can make an educated guess as to the cause of MPN, much more research is needed to identify the true cause.

How is MPN Diagnosed?

One of the biggest indicators of MPN, with the exception of essential thrombocythemia, is an enlarged spleen. Therefore, if your doctor notices an enlarged spleen during a physical exam they may conduct one of the following tests:

• Blood tests – to find abnormal types or numbers of white and red blood cells, along with detecting anemia and leukemia.
• Bone marrow biopsy – This is only usually done in order to confirm the results of the blood test. 
• Cytogenetic analysis – Viewing blood or bone marrow under a microscope to look for alterations in the chromosomes.

While these are some of the most common ways to diagnose MPN, your doctor may take a different approach based on your individual symptoms and health history.

To learn more about how patients are diagnosed with MPN, read our MPN patient stories and specialist interviews.

What are the Symptoms and Treatments for MPN?

The symptoms and treatments for MPN vary based on the type of MPN. Visit our page about MPN symptoms and treatments to learn more about MPN.

The Patient Story strives to capture the unique story of each individual diagnosed with cancer. While no one cancer patient takes the same path, learning from others’ experiences can be enlightening. Learn from other cancer patients as they share their stories.