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Causes

No single known cause for all of the different types of leukemia exists. The known causes, which are not generally factors within the control of the average person, account for relatively few cases.The different leukemias likely have different causes.
Leukemia, like other cancers, results from somatic mutations in the DNA. Certain mutations produce leukemia by activating oncogenes or deactivating tumor suppressor genes, and thereby disrupting the regulation of cell death, differentiation or division. These mutations may occur spontaneously or as a result of exposure to radiation or carcinogenic substances, and are likely to be influenced by genetic factors.
Among adults, the known causes are natural and artificial ionizing radiation, a few viruses such as Human T-lymphotropic virus, and some chemicals, notably benzene and alkylating chemotherapy agents for previous malignancies.Use of tobacco is associated with a small increase in the risk of developing acute myeloid leukemia in adults.Cohort and case-control studies have linked exposure to some petrochemicals and hair dyes to the development of some forms of leukemia. A few cases of maternal-fetal transmission have been reported.Diet has very limited or no effect, although eating more vegetables may confer a small protective benefit.
Viruses have also been linked to some forms of leukemia. For example, certain cases of ALL are associated with viral infections by either the human immunodeficiency virus or human T-lymphotropic virus (HTLV-1 and -2, causing adult T-cell leukemia/lymphoma). However, one report suggests exposure to certain germs may offer children limited protection against leukemia.
Some people have a genetic predisposition towards developing leukemia. This predisposition is demonstrated by family histories and twin studies.The affected people may have a single gene or multiple genes in common. In some cases, families tend to develop the same kind of leukemia as other members; in other families, affected people may develop different forms of leukemia or related blood cancers.
n addition to these genetic issues, people with chromosomal abnormalities or certain other genetic conditions have a greater risk of leukemia. For example, people with Down syndrome ave a significantly increased risk of developing forms of acute leukemia, and Fanconi anemia is a risk factor for developing acute myeloid leukemia.
Whether non-ionizing radiation causes leukemia has been studied for several decades. The International Agency for Research on Cancer expert working group undertook a detailed review of all data on static and extremely low frequency electromagnetic energy, which occurs naturally and in association with the generation, transmission, and use of electrical power.hey concluded that there is limited evidence that high levels of ELF magnetic (but not electric) fields might cause childhood leukemia. Exposure to significant ELF magnetic fields might result in twofold excess risk for leukemia for children exposed to these high levels of magnetic fields.However, the report also says that methodological weaknesses and biases in these studies have likely caused the risk to be overstated. No evidence for a relationship to leukemia or an other form of malignancy in adults has been demonstrated. Since exposure to such levels of ELFs is relatively uncommon, the World Health Organization concludes that ELF exposure, if later proven to be causative, would account for just 100 to 2400 cases worldwide each year, representing 0.2 to 4.95% of the total incidence for that year.
Until the cause or causes of leukemia are found, there is no way to prevent the disease. Even when the causes become known, they may not be readily controllable, such as naturally occurring background radiation, and therefore not especially helpful for prevention purposes.

Treatment

Most forms of leukemia are treated with pharmaceutical medications, typically combined into a multi-drug chemotherapy regimen. Some are also treated with radiation therapy. In some cases, a bone marrow transplant is useful.

Acute lymphoblastic leukemia (ALL)

Management of ALL focuses on control of bone marrow and systemic (whole-body) disease. Additionally, treatment must prevent leukemic cells from spreading to other sites, particularly the central nervous system (CNS) e.g. monthly lumbar punctures. In general, ALL treatment is divided into several phases:
Induction chemotherapy to bring about bone marrow remission. For adults, standard induction plans include prednisone, vincristine, and an anthracycline drug; other drug plans may include L-asparaginase or cyclophosphamide. For children with low-risk ALL, standard therapy usually consists of three drugs (prednisone, L-asparaginase, and vincristine) for the first month of treatment.
Consolidation therapy or intensification therapy to eliminate any remaining leukemia cells. There are many different approaches to consolidation, but it is typically a high-dose, multi-drug treatment that is undertaken for a few months. Patients with low- to average-risk ALL receive therapy with antimetabolite drugs such as methotrexate and 6-mercaptopurine (6-MP). High-risk patients receive higher drug doses of these drugs, plus additional drugs.
CNS prophylaxis (preventive therapy) to stop the cancer from spreading to the brain and nervous system in high-risk patients. Standard prophylaxis may include radiation of the head and/or drugs delivered directly into the spine.
Maintenance treatments with chemotherapeutic drugs to prevent disease recurrence once remission has been achieved. Maintenance therapy usually involves lower drug doses, and may continue for up to three years.
Alternatively, allogeneic bone marrow transplantation may be appropriate for high-risk or relapsed patients.