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Additional Information
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What Is Leukemia?
Leukemia is a type of cancer.
Cancer is a group of many related diseases. All cancers begin
in cells,
which make up blood and
other tissues.
Normally, cells grow and divide to form new cells as the
body needs them. When cells grow old, they die, and new cells
take their place.
Sometimes this orderly process goes wrong. New cells form
when the body does not need them, and old cells do not die
when they should. Leukemia is cancer that begins in blood
cells.
Normal Blood Cells
Blood cells form in the bone
marrow. Bone marrow is the soft material
in the center of most bones.
Immature blood cells are called stem
cells and blasts.
Most blood cells mature in the bone marrow and then move
into the blood
vessels. Blood flowing through the blood vessels
and heart is called the peripheral
blood.
The bone marrow makes different types of blood cells. Each
type has a special function:
- White
blood cells help fight infection.
- Red
blood cells carry oxygen to tissues throughout
the body.
- Platelets help
form blood clots that control bleeding.
Leukemia Cells
In people with leukemia, the bone marrow produces abnormal
white blood cells. The abnormal cells are leukemia cells.
At first, leukemia cells function almost normally. In time,
they may crowd out normal white blood cells, red blood cells,
and platelets. This makes it hard for blood to do its work.
Types of Leukemia
The types of leukemia are grouped by how quickly the disease
develops and gets worse. Leukemia is either chronic (gets
worse slowly) or acute (gets
worse quickly):
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Chronic
leukemia—Early in the disease,
the abnormal blood cells can still do their work,
and people with chronic leukemia may not have any symptoms.
Slowly, chronic leukemia gets worse. It causes
symptoms as the number of leukemia cells in the
blood rises.
-
Acute
leukemia—The blood cells
are very abnormal. They cannot carry out their
normal work. The number of abnormal cells increases
rapidly. Acute leukemia worsens quickly.
The types of leukemia are also grouped by the type of white
blood cell that is affected. Leukemia can arise in lymphoid cells
or myeloid cells.
Leukemia that affects lymphoid cells is called lymphocytic leukemia.
Leukemia that affects myeloid cells is called myeloid leukemia
or myelogenous leukemia.
There are four common types of leukemia:
-
Chronic
lymphocytic leukemia (chronic
lymphoblastic leukemia, CLL) accounts
for about 7,000 new cases of leukemia each year.
Most often, people diagnosed with the disease are
over age 55. It almost never affects children.
-
Chronic
myeloid leukemia (chronic
myelogenous leukemia, CML) accounts for
about 4,400 new cases of leukemia each year. It
affects mainly adults.
-
Acute
lymphocytic leukemia (acute
lymphoblastic leukemia, ALL) accounts
for about 3,800 new cases of leukemia each year.
It is the most common type of leukemia in young
children. It also affects adults.
-
Acute
myeloid leukemia (acute
myelogenous leukemia, AML) accounts for
about 10,600 new cases of leukemia each year. It
occurs in both adults and children.
Hairy
cell leukemia is a rare type of chronic leukemia.
This booklet does not deal with hairy cell leukemia or
other rare types of leukemia. Together, these rare leukemias
account for about 5,200 new cases of leukemia each year.
The Cancer Information Service (1-800-4-CANCER) can provide
information about these types of leukemia.
To read the rest of this great article from the National
Cancer Institute, please click here: http://www.nci.nih.gov/cancertopics/wyntk/leukemia/page5
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Additional
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