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Leukemia and other diseases of the blood and bone marrow may affect red blood cells, white blood cells, and platelets.
Normally, the bone marrow makes blood stem cells (immature cells) that develop into mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell. The lymphoid stem cell develops into a white blood cell. The myeloid stem cell develops into one of three types of mature blood cells:

Blood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell.
Childhood acute myeloid leukemia (AML) is a type of cancer in which the bone marrow makes a large number of abnormal blood cells.
Cancers that are acute usually get worse quickly if they are not treated. Cancers that are chronic usually get worse slowly. Acute myeloid leukemia (AML) is also called acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia, or acute nonlymphocytic leukemia.
In AML, the myeloid stem cells usually develop into a type of immature white blood cell called myeloblasts (or myeloid blasts). The myeloblasts, or leukemia cells, in AML are abnormal and do not become healthy white blood cells. The leukemia cells can build up in the blood and bone marrow so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or easy bleeding may occur. The leukemia cells can spread outside the blood to other parts of the body, including the central nervous system (brain and spinal cord), skin, and gums. Sometimes leukemia cells form a solid tumor called a granulocytic sarcoma or chloroma.
There are subtypes of AML based on the type of blood cell that is affected. The treatment of AML is different when it is a subtype called acute promyelocytic leukemia (APL) or when the child has Down syndrome.
Other myeloid diseases can affect the blood and bone marrow.
Chronic myelogenous leukemia
In chronic myelogenous leukemia (CML), too many bone marrow stem cells develop into a type of white blood cell called granulocytes. Some of these bone marrow stem cells never become mature white blood cells. These are called blasts. Over time, the granulocytes and blasts crowd out the red blood cells and platelets in the bone marrow. CML is rare in children.
Juvenile myelomonocytic leukemia
Juvenile myelomonocytic leukemia (JMML) is a rare childhood cancer that occurs more often in children around the age of 2 years. In JMML, too many bone marrow stem cells develop into 2 types of white blood cells called myelocytes and monocytes. Some of these bone marrow stem cells never become mature white blood cells. These immature cells, called blasts, are unable to do their usual work. Over time, the myelocytes, monocytes, and blasts crowd out the red blood cells and platelets in the bone marrow. When this happens, infection, anemia, or easy bleeding may occur.
Transient myeloproliferative disorder
Transient myeloproliferative disorder (TMD) is a disorder of the bone marrow that can develop in newborns who have Down syndrome. This disorder usually goes away on its own within the first 3 weeks of life. Infants who have Down syndrome and TMD have an increased chance of developing AML before the age of 3 years.
Myelodysplastic syndromes
In myelodysplastic syndromes (MDS), the bone marrow makes too few red blood cells, white blood cells, and platelets. These blood cells may not mature and enter the blood. The treatment for MDS depends on how much lower than normal the number of red blood cells, white blood cells, or platelets is. MDS may progress to AML.
This summary is about childhood AML, childhood CML, JMML, TMD, and MDS. See the following PDQ summaries for more information about other types of leukemia and diseases of the blood and bone marrow:
The risk factors for developing childhood AML, childhood CML, JMML, TMD, and MDS are similar.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Possible risk factors for childhood AML, childhood CML, JMML, TMD, and MDS include the following:
Possible signs of childhood AML, childhood CML, JMML, or MDS include fever, feeling tired, and easy bleeding or bruising.
These and other symptoms may be caused by childhood AML, childhood CML, JMML, or MDS. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:
The symptoms of TMD may include the following:
Tests that examine the blood and bone marrow are used to detect (find) and diagnose childhood AML, childhood CML, JMML, TMD, and MDS.
The following tests and procedures may be used:
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options for childhood AML depend on the following:
The prognosis and treatment options for childhood CML depend on how long it has been since the patient was diagnosed and how many blast cells are in the blood.
The prognosis (chance of recovery) and treatment options for JMML depend on the following:
The prognosis (chance of recovery) and treatment options for MDS depend on the following:
PDQ is a comprehensive cancer database available on NCI's Web site.
PDQ is the National Cancer Institute's (NCI's) comprehensive cancer information database. Most of the information contained in PDQ is available online at NCI's Web site. PDQ is provided as a service of the NCI. The NCI is part of the National Institutes of Health, the federal government's focal point for biomedical research.
PDQ contains cancer information summaries.
The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries are available in two versions. The health professional versions provide detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions provide current and accurate cancer information.
The PDQ cancer information summaries are developed by cancer experts and reviewed regularly.
Editorial Boards made up of experts in oncology and related specialties are responsible for writing and maintaining the cancer information summaries. The summaries are reviewed regularly and changes are made as new information becomes available. The date on each summary ("Date Last Modified") indicates the time of the most recent change.
PDQ also contains information on clinical trials.
A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." In the United States, about two-thirds of children with cancer are treated in a clinical trial at some point in their illness.
Listings of clinical trials are included in PDQ and are available online at NCI's Web site. Descriptions of the trials are available in health professional and patient versions. For additional help in locating a childhood cancer clinical trial, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
The PDQ database contains listings of groups specializing in clinical trials.
The Children's Oncology Group (COG) is the major group that organizes clinical trials for childhood cancers in the United States. Information about contacting COG is available on the NCI Web site or from the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
Last Revised: 2010-10-28
If you want to know more about cancer and how it is treated, or if you wish to know about clinical trials for your type of cancer, you can call the NCI's Cancer Information Service at 1-800-422-6237, toll free. A trained information specialist can talk with you and answer your questions.
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