About 4,400 new cases of chronic myelogenous leukemia (CML) are diagnosed each year in the United States. Chronic myelogenous leukemia may be called by several names, including chronic granulocytic, chronic myelocytic or chronic myeloid leukemia.
CML results from an acquired (not inherited) injury to the DNA of a stem cell in the marrow. This injury is not present at birth. Scientists do not yet understand what produces this change in the DNA in patients with CML. This change in the stem cell’s DNA confers a growth and survival advantage on the malignant stem cell. The result of this injury is the uncontrolled growth of white cells leading, if unchecked, to a massive increase in their concentration in the blood. Unlike acute myelogenous leukemia (AML), chronic myelogenous leukemia permits the development of mature white blood cells that generally can function normally. This important distinction from acute leukemia accounts for the less severe early course of the disease.
Most cases of chronic myelogenous leukemia occur in adults, but children may develop the disease. Chronic myelogenous leukemia accounts for about 4 percent of childhood leukemia cases. Childhood cases (under 20 years of age) represent about 2 percent of all patients who develop chronic myelogenous leukemia. The frequency of the disease increases with age from about one in 1 million children in the first 10 years of life to one in 100,000 people at age 50, to one in 10,000 people at age 80 and above. The disease in children is similar in behavior to that of adults; however, the outcome of stem cell transplantation is better in younger individuals.
Chronic myelogenous leukemia is distinguished from other leukemias by the presence of a genetic abnormality in blood cells, called the Philadelphia chromosome. The changes that result in this chromosome “causing” chronic myelogenous leukemia have been studied intensively. In 1960, two physicians studying chromosomes in cancer cells noticed that a chromosome in CML patients was shorter in length than that of the same chromosome in normal cells. They named this shortened chromosome the Philadelphia chromosome, because the observation was made at the University of Pennsylvania School of Medicine in that city.The total of 46 chromosomes in normal human cells is composed of 22 pairs of chromosomes numbered 1 to 22 and two sex chromosomes (either an X and Y in males or two X’s in females).
The Philadelphia chromosome (No. 22), which is an abnormally short chromosome, is usually referred to as the Ph-chromosome.
Further studies established that two chromosomes, usually chromosome Nos. 9 and 22, were abnormal. Pieces of the chromosomes, which are broken off in the blood cells of patients with chronic myelogenous leukemia, switch with each other. The detached portion of chromosome 9 sticks to the broken end of chromosome 22, and the detached portion of chromosome 22 sticks to the broken end of chromosome 9. This abnormal exchange of parts of chromosomes is called a translocation. This translocation of chromosome pieces occurs only in the stem cell and in the various blood cells derived from that stem cell. The chromosomes of the cells in other tissues are normal.
The cause of the chromosomal breakage in virtually all CML patients is not known. In a small proportion of patients, the cause of the breakage is exposure to very high doses of radiation. This effect has been most carefully studied in the Japanese survivors of the atomic bomb, whose leukemia risk was significantly increased. A slight increase in risk also occurs in some individuals treated with high dose radiotherapy for other cancers, such as lymphoma. Exposures to diagnostic dental or medical x-rays have not been associated with a heightened risk of chronic myelogenous leukemia.
The onset of chronic myelogenous leukemia is associated with symptoms that usually develop gradually. Most patients feel a loss of well-being. They tire more easily and may feel short of breath when physically active. They may have a pale complexion from anemia. Discomfort on the left side of the abdomen from an enlarged spleen is a frequent complaint. Patients may experience excessive sweating, weight loss and inability to tolerate warm temperatures. Increasingly, the disease is discovered during the course of a “routine” medical examination. Since the disease worsens over weeks or months, most patients would have symptoms develop soon after such a medical examination in any case.
To diagnose the disease, the blood and, in most cases, the marrow cells must be examined. The white cell count invariably increases, often to very high levels. Examination of the stained (dyed) blood cells with a light microscope shows a characteristic pattern of white cells: a small proportion of very immature cells (leukemic blast cells), and a larger proportion of maturing and fully-matured white cells (myelocytes and neutrophils).
Courtesy of the Leukemia and Lymphoma Society.
Conditions that suggest Leukemia, Chronic Myelogenous (CML)
Leukemia, Chronic Myelogenous (CML) suggests the following may be present
Zinc Requirement
It was found that the copper to zinc ratio was significantly higher in patients with lymphoma or acute and chronic leukemias compared to control subjects. A person at increased risk of one of these cancers should check blood levels of copper and zinc to rule out abnormalities and make adjustments accordingly. Since zinc and copper are antagonistic, and zinc deficiency is relatively common, supplemental zinc is often used to improve this ratio. Zinc helps block the absorption of copper and acts to remove accumulated copper from the body as well as prevent its accumulation. [Rev. Invest. Clin, Nov-Dec. 1995;47(6): pp.447-52]
Recommendations for Leukemia, Chronic Myelogenous (CML)
Key
| Weak or unproven link |
| Strong or generally accepted link |
| Likely to help |
Glossary
Chronic
Usually Chronic illness: Illness extending over a long period of time.
Leukemia
Cancer of the lymph glands and bone marrow resulting in overproduction of white blood cells (related to Hodgkin's disease).
DNA
Deoxyribonucleic acid, the large molecule that is the main carrier of genetic information in cells. DNA is found mainly in the chromosomes of cells.
Malignant
Dangerous. mainly used to describe a cancerous growth -- when used this way, it means the growth is cancerous and predisposed to spreading.
Acute
An illness or symptom of sudden onset, which generally has a short duration.
White Blood Cell
(WBC): A blood cell that does not contain hemoglobin: a blood corpuscle responsible for maintaining the body's immune surveillance system against invasion by foreign substances such as viruses or bacteria. White cells become specifically programmed against foreign invaders and work to inactivate and rid the body of a foreign substance. Also known as a leukocyte.
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Lymphoma
Any tumor of the lymphatic tissues.
Anemia
A condition resulting from an unusually low number of red blood cells or too little hemoglobin in the red blood cells. The most common type is iron-deficiency anemia in which the red blood cells are reduced in size and number, and hemoglobin levels are low. Clinical symptoms include shortness of breath, lethargy and heart palpitations.
Copper
An essential mineral that is a component of several important enzymes in the body and is essential to good health. Copper is found in all body tissues. Copper deficiency leads to a variety of abnormalities, including anemia, skeletal defects, degeneration of the nervous system, reproductive failure, pronounced cardiovascular lesions, elevated blood cholesterol, impaired immunity and defects in the pigmentation and structure of hair. Copper is involved in iron incorporation into hemoglobin. It is also involved with vitamin C in the formation of collagen and the proper functioning in central nervous system. More than a dozen enzymes have been found to contain copper. The best studied are superoxide dismutase (SOD), cytochrome C oxidase, catalase, dopamine hydroxylase, uricase, tryptophan dioxygenase, lecithinase and other monoamine and diamine oxidases.
Zinc
An essential trace mineral. The functions of zinc are enzymatic. There are over 70 metalloenzymes known to require zinc for their functions. The main biochemicals in which zinc has been found to be necessary include: enzymes and enzymatic function, protein synthesis and carbohydrate metabolism. Zinc is a constituent of insulin and male reproductive fluid. Zinc is necessary for the proper metabolism of alcohol, to get rid of the lactic acid that builds up in working muscles and to transfer it to the lungs. Zinc is involved in the health of the immune system, assists vitamin A utilization and is involved in the formation of bone and teeth.