Skip to content
My WebMD Sign In, Sign Up

Cancer Health Center

Font Size

Understanding Leukemia -- the Basics

What Is Leukemia?

Leukemia is an abnormal rise in the number of white blood cells. The white blood cells crowd out other blood cell elements such as red blood cells and platelets. The elevated white blood cells are immature and do not function properly.

Leukemia -- the term derives from the Greek words for "white" and "blood" -- is often considered a disease of children, yet it actually affects far more adults. It is more common in men than women and in Caucasians than African-Americans. There will be more than 52,000 new patients diagnosed with all forms of leukemia in the United States in 2014 with about 24,000 deaths.

Recommended Related to Cancer

Stages of Childhood Acute Myeloid Leukemia and Other Myeloid Malignancies

Once childhood acute myeloid leukemia (AML) has been diagnosed, tests are done to find out if the cancer has spread to other parts of the body. The extent or spread of cancer is usually described as stages. In childhood acute myeloid leukemia (AML), the subtype of AML and whether the leukemia has spread outside the blood and bone marrow are used, instead of the stage, to plan treatment. The following tests and procedures may be used to determine if the leukemia has spread: Lumbar...

Read the Stages of Childhood Acute Myeloid Leukemia and Other Myeloid Malignancies article > >

Blood has three types of cells: white blood cells that fight infection, red blood cells that carry oxygen, and platelets that help blood to clot, all suspended in its liquid plasma. Every day, hundreds of billions of new blood cells are produced in the bone marrow -- most of them red cells. In people with leukemia, however, the body starts producing more white cells than it needs. Many of the extra white cells do not mature normally, yet they tend to live well beyond their normal life span.

Despite their vast numbers, these leukemia cells are unable to fight infection the way normal white blood cells do. As they accumulate, they interfere with vital organ functions, including the production of healthy blood cells. Eventually, the body does not have enough red blood cells to supply oxygen, enough platelets to ensure proper clotting, or enough normal white blood cells to fight infection. This results in persons with leukemia being anemic as well as increasing their risks of bruising, bleeding, and infection.

Cases of leukemia are classified as acute or chronic. The cells in acute leukemia start multiplying before they develop beyond their immature stage. Chronic leukemia progress more slowly, with the leukemia cells developing to full maturity. Leukemia is further classified according to the type of white blood cell involved, most commonly myeloid or lymphoid. Under a microscope, the two main types of white blood cells are easily distinguishable as myeloid cells contain tiny particles or granules; lymphoid cells usually do not.

What Causes Leukemia?

No one knows exactly what causes leukemia. Certain chromosome abnormalities have been associated with leukemia, but they do not cause it. For example, virtually all people with chronic myeloid leukemia (CML) and some with acute lymphocytic leukemia (ALL) have an abnormal chromosome known as the Philadelphia Chromosome in their white blood cells and bone marrow. As with other leukemia types, the chromosome abnormality is an acquired abnormality; it is neither inherited nor passed on to one's children.

Genetic disorders associated with acute myeloid leukemia (AML) include Down syndrome, Bloom syndrome, Fanconi anemia, or immune deficiency disorders such as Wiskott-Aldrich syndrome and ataxia-telangectasia. In addition, at least one virus in the same family as the human immunodeficiency virus (HIV) has been associated with a rare form of the disease -- the HTLV-1 virus.

WebMD Medical Reference

Today on WebMD

Building a Support System
Blog
cancer fighting foods
SLIDESHOW
 
precancerous lesions slideshow
SLIDESHOW
quit smoking tips
SLIDESHOW
 
Jennifer Goodman Linn self-portrait
Blog
what is your cancer risk
HEALTH CHECK
 
colorectal cancer treatment advances
Video
breast cancer overview slideshow
SLIDESHOW
 
prostate cancer overview
SLIDESHOW
lung cancer overview slideshow
SLIDESHOW
 
ovarian cancer overview slideshow
SLIDESHOW
Actor Michael Douglas
Article