What is Mixed Phenotype Leukemia (MPAL)?
Mixed phenotype leukemia is a very rare type of leukemia where more than one type of leukemia occurs at the same time. This can happen when a person has either:
- Both acute lymphoblastic leukemia (ALL) blasts (cancer cells) and acute myeloblastic leukemia (AML) blasts at the same time
- Leukemic blasts that have features of both ALL and AML on the same cell
Depending on the type, MPAL can also be called mixed lineage leukemia, hybrid leukemia, biphenotypic leukemia, or bilineage leukemia.
Understanding Mixed Phenotype Leukemia (MPAL)
Leukemia is a cancer of blood cells. It most commonly involves white blood cells which help fight infection. In leukemia, young blood cells in the bone marrow do not mature properly to carry out their normal function. Instead these cancer cells, also called blasts, divide and spread – crowding out other kinds of blood cells that form in the bone marrow. This causes shortages of healthy white cells, red blood cells (which carry oxygen) and platelets (which help your blood clot when needed).
MPAL can occur over a short period of days to weeks. Early symptoms of MPAL are often related to problems with the bone marrow:
- Anemia: Tiredness, pale skin, irritability and possibly faster breathing
- Bleeding or bruising: Bruising more easily, and possibly tiny red dots (“petechiae”) on your skin
- Recurrent infections: Getting sick more often (repeated viral or bacterial infections with a fever, runny nose and cough)
- Bone and joint pain: Pain that mimics arthritis joint pain
- Abdominal distress: Pain in the belly, poor appetite, weight loss
- Swollen lymph nodes: Swelling in the lymph nodes under your arms or in your groin, chest or neck
- Trouble breathing: Wheezing, coughing or painful breathing (seek prompt medical attention if you have these symptoms)
While these are the common symptoms of leukemia, they are also common symptoms of other disorders. Always talk with your doctor for a diagnosis.
In addition to a complete medical history and physical exam, your doctor may order a number of tests to diagnose MPAL. Some of these tests help identify the exact type of cancer, while others find out whether the leukemia has invaded any specific organs. Your doctor uses all of this information to come up with the best treatment plan. Diagnostic procedures for MPAL include:
- Bone marrow aspiration and biopsy: While you are under general anesthesia, a special hollow needle is used to remove a bone marrow sample, which is tested to find out the type of cancer.
- Complete blood count (CBC): A blood sample is drawn and tested to look at the size, number and stage of growth of different blood cells.
- Additional blood tests: These may include blood chemical levels, liver and kidney tests and genetic tests.
- X-ray: Invisible electromagnetic energy beams make a picture of tissues, bones and organs.
- Spinal tap / lumbar puncture: While you are under general anesthesia, a special needle is placed into the spinal canal below the level of your back where the spinal cord ends. The pressure is checked, and a small amount of cerebral spinal fluid (CSF) is removed. This sample is tested for infection or other problems.
The specialists at Cincinnati Children’s will look at your needs and recommend a treatment plan that best suits you. Treatment usually begins by taking care of the early symptoms you are experiencing, often anemia (too few red blood cells), bleeding or infection.
Typically, you will then have a month of intense chemotherapy, much of which will occur in the hospital. It is designed to kill as many cancer cells as possible using chemotherapy. Your care team will perform tests during the recovery period to see how well your treatment plan is working.
Based on how your leukemia responds to initial therapy, treatment for MPAL may include:
- Chemotherapy: Strong medicines are given by mouth or through an IV (intravenously). These drugs target cells that are growing fast, as cancer cells do. Side effects are common because these strong drugs can also harm some normal cells.
- Intrathecal (spinal) medications / chemotherapy: A needle is used to give medicine into the area around the spinal cord.
- Radiation therapy: Targeted energy, such as X-rays, kills leukemia cells. It can help with pain from a swollen liver, spleen or lymph nodes. It can also relieve pain from bone marrow expansion.
- Blood and bone marrow / stem cell transplantation: First, high-dose chemotherapy, and possibly radiation, is given to destroy the cancer cells in the bone marrow. Fresh, healthy stem cells are then needed to replace the bone marrow cells that have been killed. To do this, donor stem cells are given by IV. From the blood stream, they make their way to the bone marrow. These fresh stem cells then start making normal white blood cells, red blood cells and platelets.
- Biological / immunological therapy: Antibodies against the cancer cells are given. These may help the body’s immune system find and kill the bad cells, or they may help guide drugs or radiation directly to the cancer cells.
- Medicines: You may receive drugs to prevent or treat side effects of MPAL treatment. Medicines can also help with nausea or pain.
- Blood transfusions: Transfusions help replace red blood cells and/or platelets.
- Antibiotics: Medicines can help prevent or treat infections.
- Follow-up care: Follow-up is needed to gauge how well treatment is working. It can also help doctors know if the disease is coming back and help them manage any late effects of treatment.