Leukemia is the malignant disorder of white blood cells in which the cells become abnormal and divide without control or order. Hematopoietic stem cells, also known as hemacytoblasts, are found in bone marrow and are the precursor to erythrocytes (red blood cells), leukocytes (white blood cells) and thrombocytes (platelets). Leukemia is caused by the mutation of the bone marrow pluripotent or most primitive hematopoietic stem cells (Caldwell, 2007).
The mutations during hematopoiesis causes uncontrolled proliferation of stem cells resulting in overcrowding of bone marrow and decreased production and function of normal hematopoietic cells (Huether, 2012). The leukemic stem cells will then enter the blood stream affecting other organs such as the liver, spleen, lymphnodes, and under certain circumstances the central nervous system. The mutant clone may demonstrate unique morphologic, cytogenic, and immunophenotypic features that can be used to classify the particular type of leukemia (Caldwell, 2007).
Leukemia can be fatal if left untreated because of the inhibited ability to produce and provide normal red blood cells, white blood cells, and plates to maintain homeostatic mechanisms. There are several modifying risk factors for leukemia including: exposure to high energy radiation, exposure to benzene and certain other chemicals, exposure to herbicides and/or pesticides, drugs that cause bone marrow depression such as Cytoxan, and adults over 60 who smoke have an increased risk.
The underlining factor to all of the environmental or modifiable risk factors are the genetic mutations caused when exposed to the chemical for long periods of time. Radiation is the most commonly linked environmental factor in the development of cancers. The most convincing evidence linking radiation and the development of leukemia is research conducted after the Hiroshima nuclear bombings. The survivors of the Hiroshima attacks were monitored for several years and leukemia and tumor development were found to be the most common diseases caused by immense radiation exposure.
Scientists also evaluated the outcomes of exposure to various levels of radiation and found that the higher the radiation dose, the greater the incidence of leukemia (Bozzone, 2009). Also, there has been a linkage between the development of leukemia and those individuals receiving radiation treatment for other forms of cancer. Therefore, the relationship between radiation and leukemia is a linear one. In order to reduce the risk of leukemia or cancer in general an individual must know how to limit their exposure and radiation exposure frequently occurs.
Individuals who work with or in radiology departments are an increased risk of exposure to radiation. In the hospital setting, there are several measures that can be initiated to limit the exposure to radiations such as: using imaging systems that use the lowest possible radiation dose, beam filters, limiting the region of the body being scanned to the smallest possible area, and eliminating unnecessary exams.
General rules in limiting the exposure are: time, limit the amount of time; distance, the greater the distance the less exposure; shielding, barriers such as lead, concrete, and water give effective protection; containment, keeping the radioactive particles confined to small spaces and protected. Benzene is another environmental risk that has been linked to the increased risk of leukemia. Benzene starts off as a liquid but evaporates quickly and is produced from natural occurrences such as forest fires or volcanos.
Individuals are most often exposed to benzene through breathing in contaminated air. Those at risk for inhaling benzene are those individuals who work in tire factories, oil refineries, chemical plants, steel workers, lab technicians, and firefighters. In addition, cigarette smoke is a large contributor to the consumption of benzene among populations. Benzene has shown to be harmful in tests conducted both in laboratory setting and on humans.
Benzene alters the chemical make up in cells increasing the incidence of mutations during DNA replication. In order to limit the exposure to benzene, especially those in industries that use it for manufacturing, it is important individuals use personal protective equipment containing filtered mask and ensure the room is well ventilated. In addition, talking with employers or research facilities to determine if there is a substitute that can be used in product development.
Considering smoking is a large contributing factor to benzene exposure; stay away from cigarette smoke or if the individual is a smoker they need to quit. The other categories of chemicals associated with the development of leukemia are herbicides and pesticides. The majority of more than 30 studies in the medical literature show an association between adult leukemia’s and farming and/or herbicide/pesticide exposure (Bozzone, 2009). Just as in benzene and radiation exposure to these chemicals can alter DNA leading to mutations that have been linked to cancer.
In addition to many chemicals and radioactive particles, leukemia has been linked to many genetic abnormalities and infections. There is evidence of related genetic aberrations that are associated with the onset of malignancy such as; family history of leukemia, Down syndrome, Fanconi aplastic anemia, Bloom syndrome, trisomy 13, Patau syndrome, and some immune deficiencies (Huether, 2012). Infections that have been linked to the development of leukemia include RSV, HIV retrovirus, and hepatitis C.
The infections are acquired therefore they can be prevented through immunizations and safe sex. However, genetically abnormalities cannot be prevented but they can be monitored for early signs of leukemia development.
References Bozzone, D. (2009). Leukemia. New York, NY: Chelsea House. Caldwell, B. (2007). Hematology in Practice. Chapter 11: Acute leukemial, pp. 159-185. Huether, S. M. (2012). Understanding Pathophysiology (5th ed). St. Louis, Missouri: Elsevier Mosby.