Leukemia (leukaemia in Commonwealth English) is a group of blood diseases characterized by malignancies (cancer) of the blood-forming tissues. Leukemia is the most common childhood cancer in the industrialised world; in the UK, around one in 2000 children are affected.
The word leukemia tends to be used as an umbrella term. In the 19th century, it was seen as one single, homogenous deadly disease, characterized by a white (leuko-) appearance of blood samples. However, with growing understanding of pathologic and cytologic processes, doctors are now able to differentiate numerous diseases which require different treatment.
Leukemia, first recognised by the German pathologist Rudolf Virchow in 1847, with the first case described by British pathologist John Hughes Bennett in 1845, starts when bone marrow cells multiply abnormally. This is caused by mutations in the DNA in stem cells. Bone marrow stem cells produce billions of red blood cells and white blood cells each day, respectively carrying oxygen and fighting infection throughout the body. Leukemia is characterised by an excessive production of abnormal white blood cells, overcrowding the bone marrow and often spilling out into the peripheral blood. The infiltration of the bone marrow results in decreased production and function of normal blood cells. Leukemia, dependent on the type, can spread to the lymph nodes, spleen, liver, central nervous system and other organs or tissues.
Common Cancer Types
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