Overview

What is leukemia?

Leukemia is cancer that originates in the bone marrow, the soft, spongy center of the bone that produces blood cells. In most cases, the marrow produces too many immature white blood cells called "blasts" that are abnormally shaped. Normal lymphocytes fight off infection, but immature blasts are not able to do so.

As these blasts multiply they crowd the bone marrow and interfere with the production of red blood cells, platelets, and other types of white blood cells. This can result in:

• Anemia. Anemia happens when the body has too few red blood cells. It can make you feel tired, cranky and sleepy. You might also be pale, short of breath and have a fast heart rate.
• Bruising or bleeding problems. This happens when the platelet count is low. Platelets help the blood clot normally.
• Increased fevers and infections. Having too few normal white blood cells makes you more likely to get sick.

Each year roughly 30,500 adults and 2,800 children are diagnosed with leukemia. Treatment for leukemia has improved over the past 30 years, and this has resulted in long-term survival, and even complete remission and cure, for many people.

What are the different types of leukemia?

There are several types of leukemia classified as acute or chronic based on how fast the disease progresses and by the white blood cell type that is affected.

Acute leukemia is a disease that gets worse quickly. The bone marrow produces blasts, which are very early or immature cells incapable of useful functions. In the acute leukemias, blasts multiply quickly and overcrowd the bone marrow, squeezing out normal cells, then spill over into the bloodstream.

Chronic leukemia usually progresses slowly. An adult can have chronic leukemia for many years before it becomes a problem.

Leukemias are named by the type of white blood cell that is defective. In lymphocytic leukemia, lymphocytes are malfunctioning. In myeloid leukemia, myeloid cells are malfunctioning.

More on Leukemia

	What Is Leukemia?
	Types of Leukemia
	Will My Cancer Come Back? Coping with the Fear of Recurrence

In the Encyclopedia:

	Leukemias, acute
	Alemtuzumab
	Beta2-microglobulin test
	Bone marrow transplantation
	Leukemias, chronic

See Your Doctor if You Have

	Swollen lymph nodes in the neck, under the arm, in the groin
	Abdominal pain
	Bruises at sites of minor injury
	Lack of appetite
	Feeling tired all the time
	Bleeding easily

This article was reviewed and updated June 2007.