Leukemia
Doctor to Patient
Chronic Myelogenous Leukemia (CML) Causes, Symptoms, and Treatment
Pro athletes often seem to know their bodies, and notice bodily changes early when something isn't quite right. This intuition may have led Kareem Abdul-Jabbar to seek medical help when he started to get hot flashes and night sweats last fall. Many people may have ignored these symptoms and sloughed them off as unimportant. Hot flashes may be normal for women in menopause, but not for a male basketball legend. Mr. Abdul-Jabbar's symptoms led to an early diagnosis of chronic myelogenous leukemia (CML).
What causes chronic myelogenous leukemia?
Chronic myelogenous leukemia is a rare type of leukemia that tends to affect older males. More than 90% of cases are due to a gene abnormality caused when two chromosomes swap sections with each other. There are 23 chromosomes in humans, and in patients with chronic myelogenous leukemia chromosomes 9 and 22 within blood cells exchange bits of genetic material to form a Philadelphia chromosome, named after the city where it was discovered. The new gene on this chromosome makes a protein called tyrosine kinase that allows white blood cells to grow out of control; moreover, these abnormal white blood cells tend not to become old and die. The bone marrow, where red blood cells, white blood cells, and platelets are made, becomes filled with white blood cells crowding out the normal cells and damaging the bone marrow itself. This can impair the ability of the bone marrow to manufacture normal amounts of blood cells.
Read the rest of Chronic Myelogenous Leukemia (CML) Causes, Symptoms, and Treatment »
What is leukemia?
Leukemia is cancer that starts in the tissue that forms blood. To understand cancer, it helps to know how normal blood cells form.
Normal Blood Cells
Most blood cells develop from cells in the bone marrow called stem cells.
Bone marrow is the soft material in the center of most bones.
Stem cells mature into different kinds of blood cells. Each kind has a
special job:
White
blood cells help fight infection. There are several types of white blood cells.
Red
blood cells carry oxygen to tissues throughout the body.
Platelets help form
blood clots that control bleeding.
White blood cells, red blood cells, and platelets are made from stem cells as
the body needs them. When cells grow old or get damaged, they die, and new cells
take their place.
The picture below shows how stem cells can mature into different types of
white blood cells. First, a stem cell matures into either a myeloid stem cell or
a lymphoid stem cell:
- A myeloid stem cell matures into a myeloid blast. The blast can form a red
blood cell, platelets, or one of several types of white blood cells.
- A lymphoid stem cell matures into a lymphoid blast. The blast can form one of
several types of white blood cells, such as B cells or T cells.
The white blood
cells that form from myeloid blasts are different from the white blood cells
that form from lymphoid blasts.
Leukemia Cells
In a person with leukemia, the bone marrow makes abnormal white blood cells.
The abnormal cells are leukemia cells.
Unlike normal blood cells, leukemia cells don't die when they should. They
may crowd out normal white blood cells, red blood cells, and platelets. This
makes it hard for normal blood cells to do their work.
Next: What are the types of leukemia? »
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