Drawing described below.

This drawing shows normal blood cells and blood cells with leukemia. Platelets, red blood cells (RBC's), white blood cells (WBC's), plasma (fluid), and blast cells are labeled.

Image courtesy National Cancer Institute.external icon

Leukemia is a cancer of the bone marrow (the soft, sponge-like tissue in the center of most bones that makes blood cells) and blood. The two main kinds of leukemia are—

  • Lymphocytic leukemia (also known as lymphoblastic leukemia), is when the body makes too many of a certain kind of white blood cells, called lymphocytes.
  • Myelogenous leukemia (also known as myeloid or myelocytic leukemia), is when the body makes too many of a certain kind of white blood cells, called granulocytes.

Leukemia can be acute or chronic. Acute types of leukemia progress quickly, while chronic types of leukemia progress slowly, leading to different treatments.

Leukemia is the most common kind of cancer among children and teens. Acute lymphocytic leukemia is more common among children and teens than among adults. However, because other types of leukemia become more common with age, most leukemia is found in among adults.

What Causes Leukemia?

Scientists do not fully understand all of the causes of leukemia, but research has found many links. For example—

  • Being exposed to benzene or large doses of ionizing radiation have caused leukemia in some people.
  • Tobacco smoke contains cancer-causing chemicalsexternal icon (including benzene), which are linked to acute myeloid leukemia in adults.
  • Family history also has been linked with higher risk of some kinds of leukemia, such as chronic lymphocytic leukemia.
  • Some people with Down syndrome or blood disorders such as polycythemia veraexternal icon (a disease in which there are too many red blood cells in the bone marrow and blood, causing the blood to thicken) may be more likely to develop leukemia.
  • Most people with chronic myelogenous leukemia have a gene mutation (change) called the Philadelphia chromosome.external icon It results in the bone marrow making an enzyme that causes too many stem cells to become white blood cells. The Philadelphia chromosome is not passed from parent to child.
  • White people are more likely than black people to develop lymphocytic leukemia, but scientists do not know why. Scientists also do not know why men are more likely than women to develop leukemia.

What Are the Symptoms of Leukemia?

Chronic lymphocytic leukemia usually does not cause any symptoms and is usually found during a routine blood test. If it does cause symptoms, they can include swollen lymph nodes and feeling tired. Symptoms of chronic myelogenous leukemia include fever, night sweats, and feeling tired. Sometimes chronic myelogenous leukemia does not cause any symptoms.

The early symptoms of acute myelogenous leukemia and acute lymphocytic leukemia may be like those caused by the flu or other common diseases. Symptoms include fever, night sweats, feeling tired, feeling out of breath, and bruising or bleeding easily.

These symptoms can also come from other conditions. If you have any of them, talk to your doctor.


The Data Visualizations tool makes it easy for anyone to explore and use the latest official federal government cancer data from United States Cancer Statistics. It includes the latest cancer data covering 100% of the U.S. population.

Map of the United States.
See rates or numbers of new leukemias or leukemia deaths for the entire United States and individual states. Also, see the top 10 cancers for men and women.
Bar chart of demographics.
See rates or numbers of new leukemias or leukemia deaths by race/ethnicity, sex, and age group.
Line chart of trends.
See how the rates of new leukemias or leukemia deaths changed over time for the entire United States and individual states.
More Information