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CML is generally diagnosed via a chromosome anomaly widely known as the Philadelphia (Ph) Chromosome. (Check out the figure) The name is derived from the city where the chromosome was first discovered.
BCR-ABL produces a specific new hydrid gene, which is an enzyme called tyrosine kinase.
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Leukaemia is a form of cancer and CML is one of the four main Leukaemia types. CML starts with an abnormality in one stem cell. Although it is possible to encounter in childhood and puberty, CML is mainly an adolescence disease.
According to the statistics of USA National Cancer Institute, 5000 new CML cases are expected to be encountered in 2009. The same statistics points out that there are currently 23.000 active CML cases.
Since 2001 authorized drugs such as Imatinib, Dasatinib, Nilotinib are mainly used. Clinic researches for new drugs are already in progress. The rate of CML diagnosed patients who are living healthily is increasing with every passing day.
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And then forms an abnormal chromosome.
There are 23 pairs of chromosomes in human cells. And these chromosomes bear the DNAs which hold the gene content to control the body cells. In CML patients the pieces of the chromosomes inside the blood cells switch places. Part of chromosome 9 wrongly moves over to join chromosome 22 at a certain point thus forming the extra long 9 and extra short 22 chromosomes.
The extra short 22 chromosome is called The Philadelphia (Ph) Chromosome. Around 90% of CML patients carry this chromosome in their blood cells.
And the abnormal chromosome forms a new gene.
The Philadelphia chromosome contains a new gene, known as BCR-ABL. This gene carries the command for producing extra tyrosine kinase which is relayed to the abnormal blood cells. Tyrosine kinase stimulates the abnormal production of specific blood cells and causes the cancer to spread even more.
And finally the new gene forms loads of abnormal blood cells.
The white blood cells are formed by the bone marrow. While the bone marrow functions are normal blood stem cell is produced. Then this stem cell transforms into red corpuscles (erythrocyte), white corpuscles (leukocyte) and blood placelets (thrombocyte.)
Well in CML this process does not take place in a healthy fashion. Tyrosine kinase which is formed by the BCR-ABL gene produces extra white corpuscles. And most of these cells carry the Philadelphia Chromosome. The abnormal white cells’ life cycle in unlike the normal ones. Lots of these abnormal cells begin invading the bone marrow and gradually stops all functioning.
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- Old age,
- Being male,
- Exposure to radiation or being subject to a radiation therapy,
are among the known risk factors.
The chromosome abnormality causing CML is known to be an acquired characteristic. This mutation can take place anytime after birth.
The gene abnormality seen in CML is not inherited. And you cannot catch CML from someone who has it.
Most people subject to radiation therapy do not develop CML. The radiation amount received from medical screenings is significantly small. These amounts do not pose an increased CML threat.
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