Leukemia is not hereditary; it happens mainly randomly. However, hereditary influence and environmental exposures can influence a person's risk for leukemia. In a few rare cases, parents seem to pass on the susceptibility to the disease, and the gene that causes this seems to be designated as CBFA2. For more information on this gene and how it affects a person's susceptibility to leukemia, see Research Outlook.
Leukemia is caused when chromosomes go through translocation, or the transfer of one piece of a chromosome to a non homologous chromosome, and often the two non homologous chromosomes will swap segments. In leukemia, CML is caused by the translocation between one chromosome 9 and one chromosome 22; the translocation designated t(9;22). This results in a chromosome 9 that is longer than normal and a chromosome 22 that is shorter than normal (the Philadelphia chromosome or PH1). The gene that is removed from chromosome 9 is designated c-ABL, and it contains most of the proto-oncogene. A proto-oncogene is gene with one normal cell and one mutated cell; the mutated cell is called an oncogene, and it is dominant. The break in the chromosome 22 occurs in the middle of a gene called BCR. The resulting chromosome, the Philadelphia chromosome, contains a section of the BCR fused with most of the proto-oncogene.
There are multiple different types of leukemia, but the four most common are Acute Myeloid Leukemia (AML), Acute Lymphoblastic Leukemia (ALL), Chronic Myeloid Leukemia (CML), and Chronic Lymphoblastic Leukemia (CLL).
Acute Myeloid Leukemia (AML)
Many patients with AML need treatment as soon as possible and in some cases AML can be cured with regular therapies. This type of leukemia mostly affects cells that aren't developed, so that they are unable to perform their functions; a reason why treatment is needed as soon as possible.
Chronic Myeloid Leukemia (CML)
Many patients with CML are treated with daily oral drug therapy. This type of leukemia has three different phases, and it is normally diagnosed in its early stages when symptoms aren't as noticeable. In the first stage, the chronic stage, white blood cells can still fight infection and are treated with long-tern drug therapy. Very few individuals advance to the next phase, the accelerated phase. Within this phase, your blood may have a lower-than-normal number of red blood cells, along with a lower number of platelets. You may also experience a swollen spleen. In the next phase, the blast crises phase, you have a high number of blast cells (infected cells) in your bone marrow and blood. You may experience infection, bleeding, tiredness, stomach pain, shortness of breath, or bone pain. Once a patient has reached this phase it is life threatening.
Acute Lymphoblastic Leukemia (ALL)
This type of leukemia is the most common type of cancer in children ages one to seven, and it affects the blood cells and the immune system. There are subtypes of ALL and the treatment a person receives depends on the subtype that he or she has. It spreads rapidly without treatment, so it is important to start treatment as soon as possible after diagnosis; most children with the disease are curable with treatment.
Chronic Lymphoblastic Leukemia (CLL)
CLL is the most common type of leukemia in adults, but in some people the disease spreads faster while in others it spreads slower. In people with slow-spreading CLL, the best treatment may be watchful waiting. Many patients with this type of leukemia live good-quality lives for a long time with medical treatment.
Leukemia is a cancer that affects blood and bone marrow, and it is caused by the mutation in the DNA of blood cells. These mutations can occur naturally or be influenced by outside factors.
When white blood cells loose a piece of their DNA or their DNA is damaged a person will start to develop Leukemia. As with all cancer cells, these cells have developed a mutation so that they don’t need to go through the checkpoints in mitosis, a type of cell division. The leukemic cells are able to divided over and over again, and soon it creates an immature form that will never fully mature. However, unlike normal blood cells, these cancerous cells will not die but continue to replicate until the ratio of mutated cells is larger than the normal cells.
Another way the mutation of a white blood cell may occur is if one part of a chromosome detaches and attaches itself to another chromosome. This is called translocation and it disrupts the normal sequence of DNA along with adding the possibility of tumor growth. Radiation can cause Leukemia as well; damaging or destroying cells, and causing translocation.
The following is an informational video about Leukemia:
More Information:
The Leukemia and Lymphoma Society