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Overview of Leukemia


Ashkan Emadi

, MD, PhD, University of Maryland;

Jennie York Law

, MD, University of Maryland, School of Medicine

Reviewed/Revised Oct 2023
Topic Resources

Leukemias are cancers of white blood cells or of cells that develop into white blood cells.

White blood cells develop from stem cells in the bone marrow. Sometimes the development goes awry, and pieces of chromosomes get rearranged. The resulting abnormal chromosomes interfere with normal control of cell division, so that affected cells multiply uncontrollably or are resistant to normal cell death, resulting in leukemia.

Blood Cell Cancer

Classification of leukemia

Leukemias are grouped into four main types:

The types are defined according to how quickly they progress and the type and characteristics of the white blood cells White Blood Cells The main components of blood include Plasma Red blood cells White blood cells Platelets read more White Blood Cells that become cancerous.

Acute leukemias progress rapidly and consist of immature cells.

Chronic leukemias progress slowly and consist of more mature cells.

Lymphocytic (lymphoblastic) leukemias develop from cancerous changes in lymphocytes or in cells that normally produce lymphocytes. They may be acute or chronic.

Myeloid (myelocytic, or myelogenous) leukemias develop from cancerous changes in cells that normally produce neutrophils, basophils, eosinophils, and monocytes. They may be acute or chronic.

Complications of leukemia

Leukemia cells ultimately occupy the bone marrow, replacing or suppressing the function of cells that develop into normal blood cells. This interference with normal bone marrow cell function can lead to inadequate numbers of:

Also, the cancerous white blood cells do not function like normal white blood cells so they cannot help the body fight off infections.

Leukemia cells may also invade other organs, including the liver, spleen, lymph nodes, testes, and brain.

Causes of Leukemia

The cause of most types of leukemia is not known. Exposure to radiation, to some types of chemotherapy, or to certain chemicals (such as benzene, some pesticides, and chemicals in tobacco smoke) increases the risk of developing some types of leukemia, although leukemia develops only in a very small number of exposed people. Certain hereditary disorders, such as Down syndrome Down Syndrome (Trisomy 21) Down syndrome is a chromosome disorder caused by an extra chromosome 21 that results in intellectual disability and physical abnormalities. Down syndrome is caused by an extra chromosome 21... read more Down Syndrome (Trisomy 21) and Fanconi anemia, increase the risk as well. In some people, leukemia is caused by certain abnormalities of the chromosomes.

A virus known as human T lymphotropic virus 1 (HTLV-1), which is similar to the virus (HIV-1) that causes AIDS, is strongly suspected of causing a rare type of lymphocytic leukemia called adult T-cell leukemia. Infection with the Epstein-Barr virus Infectious Mononucleosis Epstein-Barr virus causes a number of diseases, including infectious mononucleosis. The virus is spread through kissing. Symptoms vary, but the most common are extreme fatigue, fever, sore throat... read more Infectious Mononucleosis (which also causes mononucleosis) has been associated with a rare form of lymphocytic leukemia that occurs in Asia and Africa.

Treatment of Leukemia

  • Drugs, usually chemotherapy, immunotherapy, and/or targeted therapy

  • Sometimes stem cell transplantation, radiation therapy, or surgery

Many leukemias can be effectively treated, and some can be cured. Treatment can consist of different types of drugs called

The complications of leukemia may require treatment. People may need blood transfusions if leukemia has caused severe anemia. They may need antibiotics if infections develop. If bleeding occurs, they may need platelet transfusions.

When leukemia is under control, the number of abnormal cells in the bone marrow is very low, and people are said to be in remission. If numbers of leukemia cells increase again, people are said to have a relapse.

For some people in relapse, quality of life eventually deteriorates, and the potential benefit for further treatment may be extremely limited. Keeping people comfortable may become more important than trying to modestly prolong life. Affected people and their family members must be involved in these decisions. Much can be done to provide compassionate care Treatment Options at the End of Life Often, the available choices for end-of-life care involve a decision whether to accept the likelihood of dying sooner but to be more comfortable or attempt to live slightly longer by receiving... read more , relieve symptoms, and maintain dignity.

More Information

The following English-language resource may be useful. Please note that the MANUAL is not responsible for the content of this resource.

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