Chronic myeloid leukemia (CML) is a rare cancer of the blood and bone marrow which represents 15 to 20% of adult leukemia. Although CML can occur atany age, it tends to affect adults between 30 and 50 years, but mainly adults aged over 55 years, with a slight male predominance. Chronic myeloid leukemia is favored by exposure to benzene and ionizing radiation. This is the rarest type of leukemia, coming right before hairy cell leukemia, in order of frequency: Chronic Lymphocytic Leukemia> Acute Leukemia> Chronic Myeloid Leukemia> Hairy Cell Leukemia.
The bone marrow is located inside of bones. It is the seat of manufacturing of all blood cells, which occursfrom stem cells called “hematopoietic”. Thehematopoieticstem cells (HSCs)of the bone marrow are the source of all blood cells:
• Red blood cells (erythrocytes), which carry oxygen to all organs and tissues;
• White blood cells (leukocytes), which fight against infections;
• The platelets that help the blood to clot in order to stop persistent bleeding when a blood vessel is injured.
Chronic Myeloid Leukemia Statistics
Chronic myeloid leukemia is not on common cancer in the US. According to the American Cancer Society (ACS), it is estimated that the number of people affected with CML in 2014 was as follow:
- About 5,980 new cases diagnosed : 3,130 men and 2,850 women
- About 810 people died of it: 550 men and 260 women.
Chronic Myeloid Leukemia Causes
Chronic myeloid leukemia causes are not well known to science. But it is believed that the disease is due to the appearance of a chromosomal abnormality of the bone marrow stem cells:Philadelphia chromosome (also known asPhiladelphia translocation), which is named for the cityPhiladelphia (Pennsylvania, United States) where the researchers PeterC. Nowelland Hungerford D.A. discovered it in the 60s.
The scientists believe that this anomaly results from the reciprocal translocation (exchange)between chromosomes 9 and 22. This exchange is contacted two normally distinct genes: BCR gene and ABL gene, which will form an abnormal gene called BCR-ABL fusion.
This is the occurrence of this chromosomal abnormality that leads to the development of chronic myeloid leukemia (CML). But until today, little is known about the causes of the appearance of the Philadelphia chromosome.
Chronic Myeloid Leukemia Risk Factors
As mentioned above, chronic myeloid leukemia is more common in males than in females. It occurs mostly in the elderly with a median age of 64 years at diagnosis. Based on a study conducted on the Hiroshima and Nagasaki nuclear bombing survivors, It is also found that exposure to Ionizing radiation such as Heat waves, Radiowaves, Infrared light, Ultraviolet light, X rays, and Gamma rays, increases the risk for an individual to develop the cancer.