Leukemia

What is leukemia?  

Leukemia is a type of blood cancer that begins with an abnormal change in a single white blood cell in a person’s bone marrow—the soft tissue inside your bones where most blood cells are made. Once this abnormal change occurs this abnormal cell, which is now a leukemia cell, begins to multiply. These types of cells may grow faster and survive better than healthy blood cells.  

Over time, the leukemia cells crowd out or suppress the development of normal cells. The rate at which leukemia progresses and how the cells replace the normal blood and bone marrow cells are different with each type of leukemia. 

Leukemia can be acute (severe and sudden onset) or chronic (disease progresses slowly). The four main subtypes of leukemia are:  

• Acute lymphoblastic leukemia (ALL)
• Acute myeloid leukemia (AML)
• Chronic lymphocytic leukemia (CLL)
• Chronic myeloid leukemia (CML) 

What are risk factors for leukemia?

A “risk factor” is anything that increases a person’s chance of developing a disease. 

• Age: Leukemia is most common in people over 60 years of age. The most common types in adults are AML and CLL. Leukemia is the most common cancer diagnosed in children. Acute lymphoblastic leukemia is the most common form of leukemia in children.
• Sex: Males are more likely than females to develop leukemia.
• Ethnicity/race: CLL incidence is substantially lower among Asians and higher among Ashkenazi Jews. In the United States, ALL is more common in Hispanics and whites.
• Exposure to dangerous chemicals, such as benzene or Agent Orange (a herbicide used in the Vietnam War)
• Smoking
• Previous treatment with chemotherapy or radiation
• Exposure to very high doses of radiation (for example, high doses sustained by survivors of an atomic bomb blast or a nuclear reactor accident).
• Other blood cancers
• Genetic disorders, present at birth
• Family history: People with a first-degree relative who have CLL are at increased risk for CLL.
• Some people are born with certain gene mutations that may increase their risk for leukemia. 

Knowing more about the different types of leukemia can help you be more prepared when discussing options with your doctors. 

Find facts and statistics about leukemia and other blood cancers.

Types of leukemia