MPN Awareness Day Date in the current year: September 11, 2025

The bone marrow’s main biological function is producing blood components, including red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). Red blood cells deliver oxygen to body tissues, white blood cells protect the body from infection as part of the immune system, and platelets form blood clots to “plug” injured blood vessels and stop bleeding.

In some people, a mutation causes the bone marrow to not function properly and produce an abnormal amount of blood cells, which can result in several rare blood cancers collectively known as myeloproliferative neoplasms (MPNs). “Neoplasm” refers to abnormal and excessive cell growth, “myelo” refers to bone marrow, and “proliferative” refers to rapid growth.

The three most common types of MPN are known as “classical” MPNs:

• Polycythemia vera (PV), characterized by the overproduction of red blood cells, causing the blood to thicken.
• Essential thrombocythemia (ET), characterized by the overproduction of platelets, which can cause excessive bleeding and clotting.
• Myelofibrosis (MF), in which normal blood marrow is replaced with fibrous connective tissue, resulting in the production of abnormal blood cells.

The World Health Organization lists several other MPN subcategories, including chronic myelogenous leukemia (CML), chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia, and myeloproliferative neoplasm, unclassifiable (MNP-U).

MPNs are chronic, progressive conditions, meaning they are long-lasting and worsen over time. They can develop at any age but mostly affect older adults: over 50 years old for ET and MF, and over 60 years old for PV. MPNs can sometimes develop into another type of cancer. For example, polycythemia vera can develop into myelofibrosis or acute myeloid leukemia.

While MPNs typically cannot be cured, they can be managed to control symptoms, prevent complications such as thrombosis, slow progression, and improve quality of life. With proper management, many MPN patients have a life expectancy close to normal.

MPN Awareness Day was created to encourage people living with MPNs to share their stories, give hope to newly diagnosed patients, connect the global MPN community, provide support to patients and caregivers, and advocate for further MPN research.

You can participate in MPN Awareness Day by learning more about MPNs and sharing what you’ve learned with others; donating to organizations that support MPN patients and their families or fund research; and spreading the word on social media with the hashtag #MPNAwarenessDay. If you have MPN, consider sharing your story to show others with the same diagnosis that they are not alone in their struggle—of course, only if you feel comfortable!