What Are Myeloproliferative Neoplasms?
Medically reviewed by Archana Sharma, DO
Myeloproliferative neoplasms (MPNs) are a group of blood cancers that occur when your bone marrow makes too many red blood cells, white blood cells, or platelets. If you have one of these cancers, your condition worsens over time because the extra cells build up in your bone marrow or bloodstream. As a result, symptoms like fatigue and loss of appetite can occur.
According to the National Cancer Institute, which started collecting population-based data on cancer incidence and mortality in 1973, just under 300,000 people in the United States live with some type of MPN currently.
Types of Myeloproliferative Neoplasms
All MPNs start with a mutation of a blood stem cell. These stem cells create blood cells in your bone marrow. The six types of myeloproliferative neoplasms are categorized by what type of blood cell is overproduced.
Chronic myelogenous leukemia or chronic myeloid leukemia (CML): In this slow-progressing cancer, you make too many stem cells called myeloblasts, which go on to make abnormal white blood cells
Essential thrombocythemia (ET): Causes you to produce too many blood platelets
Primary myelofibrosis (PMF): Occurs when scar tissue builds up in your bone marrow that prevents the production of normal blood cells
Polycythemia vera (PV): Makes too many red blood cells which causes your blood to become thicker and increases your white blood cell and platelet levels too
Chronic neutrophilic leukemia (CNL): Too many white blood cells called neutrophils are produced, which can build up in your blood and bone marrow
Chronic eosinophilic leukemia (CEL): Overproduces a type of white blood cell called eosinophils that can build up in your bone marrow, blood, and other tissues
MPNs are also grouped into two general categories based on whether they are associated with an abnormal gene called BCR-ABL1. BCR-ABL1 is a result of two genes mistakenly getting fused. The most common MPN to have this fusion gene is CML. The other five types of MPNs do not have BCR-ABL1.
Symptoms of Myeloproliferative Neoplasms
Most MPNs develop slowly and cause very few symptoms. You may not know you have any of these conditions until your healthcare provider finds abnormal blood counts during routine bloodwork.
When one or more of your blood cell types grow and overcrowd your bone marrow, they prevent the bone marrow from producing the correct amount of normal cells. Not having enough normal blood cells can cause a wide variety of symptoms. While symptoms don't always develop in early stages, you may notice the following symptoms as your condition progresses:
Loss of appetite
Sweating
Abdominal pain or discomfort
Bloating or feeling full
Bruising or bleeding easily
Causes
The cause of MPNs is mostly unknown. Experts don't believe that there is only one cause. However, a mutation, or an abnormal change to your genetic information, could be responsible in some cases.
A specific mutation in a gene for an enzyme called Janus Kinase 2 (JAK2) has been found in 95% of people with PV, 50% of people with ET, and 40% of people with PMF. The mutation changes the shape of the enzyme and makes JAK2 constantly active. Normally, JAK2 sends a signal to your bone marrow for cells to grow. When JAK2 is always active, it leads to uncontrolled growth of blood stem cells.
Myeloproliferative leukemia virus oncogene (MPL) is another gene mutated in about 10% of people with PMFs and 6% of people with ET. MPL is the gene for a protein called thrombopoietin receptor that plays a major role in white blood cell growth and survival. Mutations of MPL also cause the protein to be constantly active.
Another gene that can be mutated is calreticulin (CALR). One specific mutation is found in about 50% to 75% of people with ET and PMF. CALR produces a protein that is normally involved in cell growth, maturity, and death. A mutation in the CALR gene can make these proteins grow and work out of control, which can play a role in the development of MPNs.
Diagnosis
Most people who receive a diagnosis for a myeloproliferative neoplasm are older in age. In fact, the median age of diagnosis is 65 years old. If you suspect symptoms of an MPN, it's important to see your healthcare provider for a proper diagnosis. Your provider will ask you questions during an office visit to learn about your medical history and then do a physical exam. Your healthcare provider may ask about:
Past illnesses and injuries
Current medications
Bleeding and clotting problems
Lifestyle habits
Your family history
If your provider suspects cancer, they will also order blood tests to make a definite diagnosis. The standard blood tests for MPNs include:
Complete blood count (CBC): Measures the number of red blood cells, white blood cells, and platelets and the amount of hemoglobin, a protein in your red blood cells that carries oxygen throughout your body
Peripheral blood smear: Takes a sample of your blood and observes the sample under a microscope to see the size, shape, and appearance of the blood cells
Blood chemistry: Assesses the levels of a wide range of chemicals like electrolytes (sodium, potassium, and chloride), fats, proteins, blood sugar, and enzymes in your blood sample
A sample of your bone marrow may also be necessary to observe under a microscope to confirm a diagnosis. Two samples are usually taken at the same time:
Bone marrow aspiration: Removes a liquid sample of your bone marrow
Bone marrow biopsy: Takes out a tiny sample of your bone filled with marrow
Treatment
Because MPNs are a group of cancers, there is not just one treatment for all MPNs. Treatments can vary in type and when and how to use it. Your provider may also recommend a combination of treatments. The five standard types of treatment are:
Chemotherapy to kill cancer cells
Medications to treat symptoms
Radiation or chemotherapy with stem cell transplantation
Targeted therapy to attack specific cancer cells
Supportive care to control your symptoms
Your treatment plan may change over time. Your MPN can stop responding to treatment, or your disease could worsen to become more aggressive if your current treatment is not enough. Continue to work with your healthcare provider to find a new treatment plan if you feel like symptoms are not improving.
How To Prevent MPNs
Unfortunately, there is no way to prevent the development of MPNs. The root cause of all MPNs is abnormal blood stem cells and researchers don't currently know a way of changing these cells to go back to normal. However, with treatment, the progression of your cancer can slow down or stop altogether. Your healthcare provider can work with you to find a treatment plan that will work best for your type of MPN to prevent your condition from worsening.
Related Conditions
Over time, your cancer can progress to a more aggressive type of MPN or a different type of blood cancer. Most commonly, your MPN could turn into acute myeloid leukemia (AML). AML is a cancer of myeloid cells in your bone marrow that develop into certain white blood cells. The cancer cells move quickly into your bloodstream. It's worth noting that AML is a fast-growing, fast-spreading cancer.
Living With Myeloproliferative Neoplasms
Like any other type of cancer, living with an MPN can be challenging. Unfortunately, having an MPN also increases your risk of other health conditions, like blood clots and heart disease. Your symptoms can also worsen over time, which may affect your ability to carry out daily activities and emotional well-being.
It's OK to feel overwhelmed about your diagnosis. However, if you or a loved one have an MPN, it's important to stay in contact with your healthcare provider or oncologist (a doctor who specializes in the treatment of cancer). They can help you adjust your treatment plan and implement lifestyle changes that can help you cope with your condition. Leaning on your loved ones and meeting with a mental health provider may also help reduce stress and make you feel supported.
Frequently Asked Questions
What is the survival rate for myeloproliferative neoplasms?
Depending on the type of MPN, the 5-year survival rate is about 50%. This means that after five years, 50% of people with an MPN are still alive.
What is the difference between leukemia and myeloproliferative disorders?
In both diseases, the abnormal cancer cells start in the bone marrow. Myeloproliferative disorders produce mature cells, but leukemia produces immature cells.
What foods should you eat with a myeloproliferative neoplasm?
Eating a healthy diet that includes a wide variety of foods and plenty of water will help you feel better and stronger so you can cope with the symptoms and treatment of your cancer.
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