Leukemia is a cancer that mostly affects white blood cells. White blood cells (also called leukocytes) fight infections.
Bone marrow is a spongy material inside the bones that makes white blood cells, red blood cells, and platelets. With leukemia (loo-KEE-mee-uh), the bone marrow makes white blood cells that don’t work. These abnormal cells can’t protect the body from germs. They crowd the bone marrow, enter the bloodstream, and can spread to other parts of the body, like the lymph nodes, brain, or liver.
Leukemia is the most common type of cancer in children. It can be acute (fast-growing) or chronic (slow growing). Most kids and teens treated for leukemia are cured of the disease.
Juvenile myelomonocytic (mye-uh-low-mon-uh-SIT-ik) leukemia (JMML) happens when immature blood cells (called blasts) make too many myelocytes and monocytes (two types of white blood cells.) The myelocytes, monocytes, and blasts crowd the normal cells in the bone marrow and other organs in the body and cause problems.
JMML tends to happen in kids younger than age 4. Many kids have a change in their genes (a mutation) that affects the monocytes.
Some medical conditions (like neurofibromatosis type 1 and Noonan syndrome) make a child more likely to develop the disease.
JMML develops over time, taking weeks to months. At first, kids can have very few symptoms. Eventually they may develop anemia, which is when the body has too few red blood cells. This happens because the bone marrow stops making the usual amount of red blood cells.
Kids with anemia may:
When they don’t have enough platelets (PLATE-lits), kids with leukemia may bruise easily, get nosebleeds, or bleed for a long time after even a minor cut.
Other symptoms of leukemia can include:
Because their white blood cells can't fight infections, kids with leukemia are more likely to get viral or bacterial infections.
Sometimes leukemia can spread, or metastasize (meh-TASS-tuh-size). If it spreads to the brain, symptoms may include headaches, seizures, balance problems, or vision problems. If it spreads to the lymph nodes in the chest, symptoms may include breathing problems and chest pain.
Doctors check for leukemia with special tests. These include:
Chemotherapy (the use of drugs to kill cancer cells) may be given to control JMML at first. But the most effective treatment is a stem cell (bone marrow) transplant. To do this, doctors:
Researchers are looking into other treatments, such as:
Having a child being treated for cancer can feel overwhelming for any family. But you're not alone. To find support, talk to anyone on your child’s care team or a hospital social worker. Many resources are available to help you get through this difficult time.
You also can find information and support online at:
Reviewed by: Larissa Hirsch, MD
Date Reviewed: Oct 10, 2021