Mar 31, 2015

Understanding The Causes of Leukemia

Leukemia is a cancer of the bone marrow and the lymphatic system. There are different types of leukemia that can affect the health of a patient. Of these types, certain leukemia generally affect children and about 30% affect adults. Leukemia usually involves white blood cells that causes them to divide abnormally. These cells do not function properly and do not die like the normal blood cells. This causes them to crowd in the system and affect the number of normal cells. This Buzzle article will help you learn more about the leading causes of leukemia.

Leukemia causes extensive damage to the bone marrow, by displacing the normal bone marrow cells with a huge number of immature white blood cells resulting in a lack of blood platelets that are important in the process of blood clotting. This means people with leukemia will be easily bruised and bleed excessively, or develop pinprick bleeds (petechiae). White blood cells, which are involved in fighting pathogens, may be suppressed putting the patient at the risk of developing infections. The red blood cell deficiency leads to anemia, which may further cause dyspnea. However, the exact cause of leukemia is not yet understood. There are a number of factors that scientists feel are responsible for its occurrence.

These factors cause mutation in the DNA of blood cells. This causes them to grow and divide rapidly. Their life span is also more than the normal blood cells. Thus, they crowd the healthy blood cells and lead to appearance of signs and symptoms of leukemia.

Factors that Lead to Leukemia
Numerous risk factors may be responsible for DNA damage within the blood cells. The risk factors believed to have the strongest associations with leukemia include the following major causes:
  • Age - Roughly 60-70% of leukemia occur in people who are older than 50.
  • Radiation - A high risk of chronic myelogenous leukemia (CML) is caused among people who have been exposed to high doses of radiation.
  • Chemicals - Workers who are exposed to benzene are prone to having acute leukemia. If exposed to some other solvents, herbicides, and pesticides can also cause this deadly disease.
  • Viruses - The human T-cell leukemia virus I (HTLV-I) is related to acute T-cell leukemia. It can also affect humans through animal viruses.
  • Genetics - Risk of Leukemia is seen among children with Down's syndrome, which is a genetically linked chromosomal abnormality which means an extra chromosome 21. Three rare inherited disorders like Fanconi's anemia, Bloom's syndrome, and ataxia telangiectasia, also can cause leukemia.
Leukemia is also found among racial and ethnic groups with different genetic make-ups. Other factors that are suspected to be possible causes of leukemia are as follows:

a. Cigarette smoking
Cigarette smoking is a risk factor for leukemia. Chemicals in tobacco smoke include benzene, polonium-210, and polycyclic aromatic hydrocarbons (PAHs). These carcinogens (cancer-causing substances) are absorbed by the lungs and are spread via the bloodstream. It is estimated that one in four cases of acute myelogenous leukemia (AML) is the result of cigarette smoking.

b. Cancer therapy
Individuals who have undergone chemotherapy and radiation therapy for previous cancers have a greater chance of getting secondary leukemia. Acute myelogenous leukemia (AML) has been reported after chemotherapy and/or radiotherapy for various solid tumors (breast cancer, ovarian cancer), blood malignancies, and nonmalignant conditions. The chemotherapeutic agents most often associated with secondary leukemias are procarbazine, chlorambucil, etoposide, mechlorethamine, teniposide, and cyclophosphamide.

The risk is increased when these drugs are combined with radiation therapy. Most secondary leukemia cancers are developed within 9 years after treatment of Hodgkin's disease, non-Hodgkin's lymphoma, or childhood CLL. Further chemotherapy often is ineffective in patients with secondary AML; their prognosis is less favorable than that of typical AML patients.

c. Other medical therapy and events
Use of the antibiotic chloramphenicol has been linked with the development of childhood leukemia. Other medications, such as growth hormones and phenylbutazone, also have reportedly shown some associations with leukemia. Leukemia and lymphomas have been observed in recipients of organ transplants, and certain immunodeficiency syndromes are associated with leukemia (e.g., infantile X-linked agammaglobulinemia and lymphatic leukemia).

Researchers have studied the many cellular changes associated with leukemia; however it is unknown why these changes occur. Many risk factors are involved and most of them are unmodifiable (beyond control). Other factors (e.g., environmental, lifestyle-related variables) are controllable (modifiable).

d. Miscellaneous
All cancers, including leukemia, begin as a mutation in the genetic material- the DNA (deoxyribonucleic acid), within certain cells. The abnormal leukemia cells remain in an immature blast form that never matures properly. They do not die off like normal cells, but tend to multiply and accumulate within the body like I included in the first paragraph of this article.

e. DNA errors
DNA errors may occur in the form of translocations. Damage produced when part of one chromosome becomes displaced and attached to another chromosome. Translocations disrupt the normal sequencing of the genes. As a result, oncogenes (cancer-promoting genes) on the chromosomes may be "switched on," while tumor suppressors (cancer-preventing genes) may be switched off. Much leukemia contains translocations that affect the blood cell chromosomes. Physicians often test for these translocations to help diagnose leukemia, determine a patient's prognosis, and identify the error.

  • Joint pain
  • Weakness and fatigue
  • Easy Bruising
  • Swollen or bleeding gums
  • Swollen tonsils
  • Enlarged liver and spleen
  • Loss of appetite and/or weight
  • Frequent infection
  • Bone pain
  • Fever, chills, night sweats and other flu-like symptoms
  • Neurological symptoms (headache)
Until we find the cause or causes of leukemia, there is no way to prevent the disease. Even when we figure the cause, they may prove to be things which are not readily controllable, such as naturally occurring background radiation, and therefore not especially be helpful for prevention purposes. It is thus, not always possible to use preventive measures in case of leukemia.


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