Causes of Leukemia
The causes of leukemia are a matter for much debate but the bottom line is that we are just not sure as to what exactly causes leukemia. If, as most researchers and medical authorities agree, leukemia is a malignant tumor, then the question is: what causes the blood cells to behave abnormally ? Evidence from many studies indicates that a genetic change, either brought about by a mutation or removal of an enzyme system, causes the cells to divide repeatedly without constraint or fail to die when they should.
Causes of Leukemia
Supplementary evidence supports this view, like the study in 1951 which showed that, in the United States, a radiologist was 9 times more likely to end up with leukemia than non-radiologists. Another example is the studies carried out in Japan post the nuclear bomb explosions. The survivors showed an inverse relation between their distance from the epicenter of the explosion and the incidence of leukemia. This is to say that the closer the person was to the 'Ground Zero', the higher the incidence of leukemia. This goes to show that ionizing radiation is one major cause of leukemia.
In the human cells are contained the instruction for when a particular set of cells should divide, how many time should they divide and when should they die. The genes that instruct the cells to divide are called the oncogenes while those that tell cells to stop dividing or to die are called the tumor suppressor genes. One of the causes of leukemia, therefore, are mutations, whatever their origin, that turn on oncogenes or turn off the tumor suppressor genes.
Whenever a cell divides in to two cells, it must make a copy of its Di-ribo Nucleic Acid (DNA), its blueprint. Sometimes this copying process is not perfect and some errors occur inspite of the presence of repair enzymes which detect these errors and correct them. And these errors, which turn on oncogenes or turn off suppressor genes, are one of the causes of leukemia. Yet another abnormality, in which genes from one chromosome get attached to another gene (a process called translocation), may also cause leukemia.
Some other causes of leukemia, in addition to radiations and exposure to carcinogens, are chemotherapy, Down's Syndrome (or other genetic disease) and Human T-cell leukemia virus-I (HTLV-I). Some of theprobable cause of leukemia which are under investigation are proximity of mobile phones, mobile phone towers and high-voltage power lines. One of the suggested causes of leukemia - intravenous administration of Vitamin K to new-born babies - has been conclusively shot down by a UK Childhood Study led by NT Fear [1].
References
1. Fear NT, Roman E, Ansell P, Simpson J, Day N, Eden OB 'Vitamin K and childhood cancer: a report from the United Kingdom Childhood Cancer Study'
Br J Cancer 89 2003 1228-1231