Leukemia is a type of cancer. Cancer is a group of more than 100
diseases that have two important things in common. One is that
certain cells in the body become abnormal. Another is that the body
keeps producing large numbers of these abnormal cells. Leukemia is
cancer of the blood cells. To understand leukemia, it is helpful to
know about normal blood cells and what happens to them when
Normal blood cells
The blood is made up of fluid called plasma and three types of
cells. Each type has special functions.
White blood cells
(also called WBCs or leukocytes) help the body fight infections and
Red blood cells
(also called RBCs or
erythrocytes) carry oxygen from the lungs to the body's tissues and
take carbon dioxide from the tissues back to the lungs. The red
blood cells give blood its color.
thrombocytes) help form blood clots that control bleeding.
Blood cells are formed in the bone marrow, the soft, spongy
center of bones. New (immature) blood cells are called
. Some blasts stay in the marrow to mature. Some
travel to other parts of the body to mature. Normally, blood cells
are produced in an orderly, controlled way, as the body needs them.
This process helps keep us healthy.
When leukemia develops, the body produces large numbers of
abnormal blood cells. In most types of leukemia, the abnormal cells
are white blood cells. The leukemia cells usually look different
from normal blood cells, and they do not function properly.
Types of leukemia
There are several types of leukemia. They are grouped in two
ways. One way is by how quickly the disease develops and gets
worse. The other way is by the type of blood cell that is affected.
Leukemia is either acute or chronic.
In acute leukemia, the abnormal blood cells are blasts. They
remain very immature and cannot carry out their normal functions.
The number of blasts increases rapidly, and the disease gets worse
In chronic leukemia, some blast cells are present. In general,
however, these cells are more mature and can carry out some of
their normal functions. Also, the number of blasts increases less
rapidly than in acute leukemia. As a result, chronic leukemia gets
Lymphocytic and myeliod leukemias
Leukemia can arise in either of the two main types of white
blood cells-lymphoid cells or myeloid cells. When leukemia affects
lymphoid cells, it is called
myeloid cells are affected, the disease is called myeloid or
. These are the most common types of
Acute lymphocytic leukemia (ALL)
is the most common type
of leukemia in young children. This disease also affects adults,
especially those age 65 and older.
Acute myeloid leukemia (AML)
occurs in both adults and
children. This type of leukemia is sometimes called acute
nonlymphocytic leukemia (ANLL).
Chronic lymphocytic leukemia (CLL)
most often affects
adults over the age of 55. It sometimes occurs in younger adults,
but it almost never affects children.
Chronic myeloid leukemia (CML)
occurs mainly in adults.
A very small number of children also develop this disease.
Hairy cell leukemia
is an uncommon type of chronic
leukemia. There are a number of other uncommon types of
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a