|Classification and external resources|
The exact cause of leukemia is unknown. Different kinds of leukemia are believed to have different causes. Both 
Treatment may involve some combination of 
In 2012 leukemia developed in 352,000 people globally and caused 265,000 deaths.
- 1 Classification
- 2 Signs and symptoms
- 3 Causes
- 4 Diagnosis
- 5 Treatment
- 6 Epidemiology
- 7 History
- 8 Society and culture
- 9 Research directions
- 10 Pregnancy
- 11 See also
- 12 References
- 13 External links
|Acute lymphoblastic leukemia
|Chronic lymphocytic leukemia
(“myeloid” or “nonlymphocytic”)
|Acute myelogenous leukemia
(AML or myeloblastic)
|Chronic myelogenous leukemia
Clinically and pathologically, leukemia is subdivided into a variety of large groups. The first division is between its chronic forms:
- leukemia in children.
- Chronic leukemia is characterized by the excessive buildup of relatively mature, but still abnormal, white blood cells. Typically taking months or years to progress, the cells are produced at a much higher rate than normal, resulting in many abnormal white blood cells. Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy. Chronic leukemia mostly occurs in older people, but can theoretically occur in any age group.
Additionally, the diseases are subdivided according to which kind of blood cell is affected. This split divides leukemias into lymphoblastic or myelogenous leukemias:
Combining these two classifications provides a total of four main categories. Within each of these four main categories, there are typically several subcategories. Finally, some rarer types are usually considered to be outside of this classification scheme.
- Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in young children. This disease also affects adults, especially those age 65 and older. Standard treatments involve chemotherapy and radiotherapy. The survival rates vary by age: 85% in children and 50% in adults. Subtypes include precursor B acute lymphoblastic leukemia, precursor T acute lymphoblastic leukemia, Burkitt’s leukemia, and acute biphenotypic leukemia.
- Chronic lymphocytic leukemia (CLL) most often affects adults over the age of 55. It sometimes occurs in younger adults, but it almost never affects children. Two-thirds of affected people are men. The five-year survival rate is 75%. It is incurable, but there are many effective treatments. One subtype is B-cell prolymphocytic leukemia, a more aggressive disease.
- Acute myelogenous leukemia (AML) occurs more commonly in adults than in children, and more commonly in men than women. AML is treated with chemotherapy. The five-year survival rate is 40%, except for APL (Acute Promyelocytic Leukemia), which is over 90%. Subtypes of AML include acute promyelocytic leukemia, acute myeloblastic leukemia, and acute megakaryoblastic leukemia.
- Chronic myelogenous leukemia (CML) occurs mainly in adults; a very small number of children also develop this disease. Treatment is with imatinib (Gleevec in United States, Glivec in Europe) or other drugs. The five-year survival rate is 90%. One subtype is chronic myelomonocytic leukemia.
- Hairy cell leukemia (HCL) is sometimes considered a subset of chronic lymphocytic leukemia, but does not fit neatly into this pattern. About 80% of affected people are adult men. No cases in children have been reported. HCL is incurable, but easily treatable. Survival is 96% to 100% at ten years.
- B cells. It is difficult to treat, and the median survival is measured in months.
- Large granular lymphocytic leukemia may involve either T-cells or NK cells; like hairy cell leukemia, which involves solely B cells, it is a rare and indolent (not aggressive) leukemia.
- HIV. Like HIV, HTLV infects CD4+ T-cells and replicates within them; however, unlike HIV, it does not destroy them. Instead, HTLV “immortalizes” the infected T-cells, giving them the ability to proliferate abnormally. Human T cell lymphotropic virus types I and II (HTLV-I/II) are endemic in certain areas of the world.
Signs and symptoms
Damage to the bone marrow, by way of displacing the normal bone marrow cells with higher numbers of immature white blood cells, results in a lack of blood petechiae).
Finally, the red blood cell deficiency leads to pallor.
Some patients experience other symptoms, such as 
If the leukemic cells invade the medical tests.
The word leukemia, which means ‘white blood’, is derived from the disease’s namesake high white blood cell counts that most leukemia patients have before treatment. The high number of white blood cells are apparent when a blood sample is viewed under a microscope. Frequently, these extra white blood cells are immature or dysfunctional. The excessive number of cells can also interfere with the level of other cells, causing a harmful imbalance in the blood count.
Some leukemia patients do not have high white blood cell counts visible during a regular blood count. This less-common condition is called aleukemia. The bone marrow still contains cancerous white blood cells which disrupt the normal production of blood cells, but they remain in the marrow instead of entering the bloodstream, where they would be visible in a blood test. For an aleukemic patient, the white blood cell counts in the bloodstream can be normal or low. Aleukemia can occur in any of the four major types of leukemia, and is particularly common in hairy cell leukemia.
There is no single known cause for any of the different types of leukemia. The few known causes, which are not generally factors within the control of the average person, account for relatively few cases. The cause for most cases of leukemia is unknown. The different leukemias likely have different causes.
Leukemia, like other cancers, results from carcinogenic substances.
Among adults, the known causes are natural and artificial 
Some people have a genetic predisposition towards developing leukemia. This predisposition is demonstrated by family histories and 
In addition to these genetic issues, people with chromosomal abnormalities or certain other genetic conditions have a greater risk of leukemia.
Whether non-ionizing radiation causes leukemia has been studied for several decades. The 
According to a study conducted at the Center for Research in Epidemiology and Population Health in France, children born to mothers who use fertility drugs to induce ovulation are more than twice as likely to develop leukemia during their childhoods than other children.
Diagnosis is usually based on repeated lymph node biopsy can be performed to diagnose certain types of leukemia in certain situations.
Following diagnosis, blood chemistry tests can be used to determine the degree of liver and kidney damage or the effects of chemotherapy on the patient. When concerns arise about other damage due to leukemia, doctors may use an CT scans are rarely used to check lymph nodes in the chest.
Despite the use of these methods to diagnose whether or not a patient has leukemia, many people have not been diagnosed because many of the symptoms are vague, non-specific, and can refer to other diseases. For this reason, the American Cancer Society estimates that at least one-fifth of the people with leukemia have not yet been diagnosed.
Most forms of leukemia are treated with pharmaceutical bone marrow transplant is effective.
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 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 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.
Decision to treat
Hematologists base CLL treatment on both the stage and symptoms of the individual patient. A large group of CLL patients have low-grade disease, which does not benefit from treatment. Individuals with CLL-related complications or more advanced disease often benefit from treatment. In general, the indications for treatment are:
- Falling platelet count
- Progression to a later stage of disease
- Painful, disease-related overgrowth of spleen
- An increase in the rate of lymphocyte production 
CLL is probably incurable by present treatments. The primary chemotherapeutic plan is 
Many different anti-cancer drugs are effective for the treatment of AML. Treatments vary somewhat according to the age of the patient and according to the specific subtype of AML. Overall, the strategy is to control bone marrow and systemic (whole-body) disease, while offering specific treatment for the central nervous system (CNS), if involved.
In general, most oncologists rely on combinations of drugs for the initial, induction phase of chemotherapy. Such combination chemotherapy usually offers the benefits of early remission and a lower risk of disease resistance. Consolidation and maintenance treatments are intended to prevent disease recurrence. Consolidation treatment often entails a repetition of induction chemotherapy or the intensification chemotherapy with additional drugs. By contrast, maintenance treatment involves drug doses that are lower than those administered during the induction phase.
There are many possible treatments for CML, but the standard of care for newly diagnosed patients is  so that CML becomes a chronic, manageable condition.
In a more advanced, uncontrolled state, when the patient cannot tolerate imatinib, or if the patient wishes to attempt a permanent cure, then an allogeneic bone marrow transplantation may be performed. This procedure involves high-dose chemotherapy and radiation followed by infusion of bone marrow from a compatible donor. Approximately 30% of patients die from this procedure.
Decision to treat
Patients with hairy cell leukemia who are symptom-free typically do not receive immediate treatment. Treatment is generally considered necessary when the patient shows signs and symptoms such as low blood cell counts (e.g., infection-fighting neutrophil count below 1.0 K/µL), frequent infections, unexplained bruises, anemia, or fatigue that is significant enough to disrupt the patient’s everyday life.
Typical treatment approach
Patients who need treatment usually receive either one week of cladribine, given daily by intravenous infusion or a simple injection under the skin, or six months of pentostatin, given every four weeks by intravenous infusion. In most cases, one round of treatment will produce a prolonged remission.
Other treatments include rituximab infusion or self-injection with Interferon-alpha. In limited cases, the patient may benefit from splenectomy (removal of the spleen). These treatments are not typically given as the first treatment because their success rates are lower than cladribine or pentostatin.
Most patients with T-cell prolymphocytic leukemia, a rare and aggressive leukemia with a median survival of less than one year, require immediate treatment.
T-cell prolymphocytic leukemia is difficult to treat, and it does not respond to most available chemotherapeutic drugs.
In 2010, globally, approximately 281,500 people died of leukemia.
About 245,000 people in the United States are affected with some form of leukemia, including those that have achieved remission or cure. Approximately 44,270 new cases of leukemia were diagnosed in the year of 2008 in the US.
Among children with some form of cancer, about a third have a type of leukemia, most commonly 
Race is a risk factor. Hispanics, especially those under the age of 20, are at the highest risk for leukemia, while whites, Native Americans, Asians, and Alaska Natives are at higher risk than blacks.
Leukemia was first observed by pathologist Franz Ernst Christian Neumann found that one deceased leukemia patient’s bone marrow was colored “dirty green-yellow” as opposed to the normal red. This finding allowed Neumann to conclude that a bone marrow problem was responsible for the abnormal blood of leukemia patients.
By 1900 leukemia was viewed as a family of diseases as opposed to a single disease. By 1947 Boston pathologist aminopterin, a folic acid mimic, could potentially cure leukemia in children. The majority of the children with ALL who were tested showed signs of improvement in their bone marrow, but none of them were actually cured. This, however, led to further experiments.
In 1962, researchers Emil J. Freireich Jr. and Emil Frei III used combination chemotherapy to attempt to cure leukemia. The tests were successful with some patients surviving long after the tests.
Society and culture
According to Love Story is an example of this romanticization of leukemia.
In the United States around $5.4 billion is spent on treatment a year.
Significant research into the causes, prevalence, diagnosis, treatment, and prognosis of leukemia is being performed. Hundreds of clinical trials are being planned or conducted at any given time. Studies may focus on effective means of treatment, better ways of treating the disease, improving the quality of life for patients, or appropriate care in remission or after cures.
In general, there are two types of leukemia research: clinical or translational research and basic research. Clinical/translational research focuses on studying the disease in a defined and generally immediately patient-applicable way, such as testing a new drug in patients. By contrast, basic science research studies the disease process at a distance, such as seeing whether a suspected carcinogen can cause leukemic changes in isolated cells in the laboratory or how the DNA changes inside leukemia cells as the disease progresses. The results from basic research studies are generally less immediately useful to patients with the disease.
Treatment through 
Leukemia is rarely associated with pregnancy, affecting only about 1 in 10,000 pregnant women.
- Acute erythroid leukemia
- Antileukemic drugs, medications used to kill leukemia cells
- Hematologic diseases, the large class of blood-related disorders, including leukemia
- Cancer-related fatigue
- “Leukemia”. NCI. Retrieved 13 June 2014.
- Finding Cancer Statistics » Cancer Stat Fact Sheets »Chronic Lymphocytic Leukemia National Cancer Institute.
- Patients with Chronic Myelogenous Leukemia Continue to Do Well on Imatinib at 5-Year Follow-Up Medscape Medical News 2006.
- Updated Results of Tyrosine Kinase Inhibitors in CML ASCO 2006 Conference Summaries.
- Matutes, Estella. (1998) “T-cell prolymphocytic leukemia, a rare variant of mature post-thymic T-cell leukemias, has distinct clinical and laboratory characteristics and a poor prognosis.” Cancer Control Journal Volume 5 Number 1.
- Diet+and+risk+of+leukemia+in+the+Iowa+Women%27s+Health+Study&rft.aulast=Ross+JA%2C+Kasum+CM%2C+Davies+SM%2C+Jacobs+DR%2C+Folsom+AR%2C+Potter+JD&rft.au=Ross+JA%2C+Kasum+CM%2C+Davies+SM%2C+Jacobs+DR%2C+Folsom+AR%2C+Potter+JD&rft.date=August+2002&rft.genre=article&rft_id=http%3A%2F%2Fcebp.aacrjournals.org%2Fcontent%2F11%2F8%2F777.long&rft_id=info%3Apmid%2F12163333&rft.issue=8&rft.jtitle=Cancer+Epidemiol.+Biomarkers+Prev.&rft.pages=777-81&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.volume=11″ class=”Z3988″>
- Pasmant E, Ballerini P, Lapillonne H et al. SPRED1 disorder and predisposition to leukemia in children. Blood 2009; 114:1131.
- “WHO | Electromagnetic fields and public health”. Retrieved 2009-02-18.
- Hoffbrand AV, Moss PAH, and Pettit JE, “Essential Haematology”, Blackwell, 5th ed., 2006.
- National Cancer Institute. “Chronic Lymphocytic Leukemia (PDQ) Treatment: Stage Information”. Retrieved 2007-09-04.
- American Cancer Society (22 March 2012). “Typical treatment of acute myeloid leukemia (except promyelocytic M3)”. Detailed Guide: Leukemia – Acute Myeloid (AML). American Cancer Society. Retrieved 31 Oct 2012.
- “Cladribine in a weekly versus daily schedule for untreated active hairy cell leukemia: final report from the Polish Adult Leukemia Group (PALG) of a prospective, randomized, multicenter trial – Robak et al. 109 (9): 3672 – Blood”. Retrieved 2007-09-10.
- “Filgrastim for Cladribine-Induced Neutropenic Fever in Patients With Hairy Cell Leukemia – Saven et al. 93 (8): 2471 – Blood”. Retrieved 2007-09-10.
- “WHO Disease and injury country estimates”. World Health Organization. 2009. Retrieved 2009-11-11.
- Horner MJ, Ries LAG, Krapcho M, Neyman N, et al. (eds). “SEER Cancer Statistics Review, 1975–2006”. Surveillance Epidemiology and End Results (SEER). Bethesda, MD: National Cancer Institute. Retrieved 2009-11-03. “Table 1.4: Age-Adjusted SEER Incidence and U.S. Death Rates and 5-Year Relative Survival Rates By Primary Cancer Site, Sex and Time Period”
- Childhood Blood Cancers | The Leukemia & Lymphoma Society
- Facts 2012 from The Leukemia & Lymphoma Society
- Patlak, Margie. “Targeting Leukemia: From Bench to Bedside”. Breakthroughs in Bioscience. The Federation of American Societies for Experimental Biology. Retrieved 20 May 2010.
- “A Snapshot of Leukemia”. NCI. Retrieved 18 June 2014.
- Search of: leukemia – List Results – ClinicalTrials.gov
- “Understanding Clinical Trials for Blood Cancers”. Leukemia and Lymphoma Society. Retrieved 19 May 2010.
- Jaslow, Ryan. “New Leukemia Therapy Destroys Cancer by Turning Blood Cells into “Assassins““. CBSnews.com HealthPop section. Retrieved 11 August 2011.
- Coghlan, Andy (26 March 2013) Gene therapy cures leukaemia in eight days The New Scientist, Retrieved 15 April 2013
- “How we’re beating leukaemia”. Retrieved 24 September 2013.
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