Most cases of<unk>  do not have exposure to any identified risk factors. That said, a number of risk factors for developing<unk>  have been identified. These include other blood disorders, chemical exposures, ionizing radiation, and genetic risk factors. Where a defined exposure to past chemotherapy, radiotherapy , toxin or hematologic malignancy is known, this is termed secondary<unk> . Other blood disorders Other blood disorders, particularly<unk> ysplastic syndrome (MDS) and less commonly myeloproliferative neoplasms (MPN), can evolve into<unk> ; the exact risk depends on the type of MDS/MPN. The presence of asymptomatic clonal hematopoiesis also raises the risk of transformation into<unk> . Chemical exposure Exposure to anticancer chemotherapy, in particular alkylating agents, can increase the risk of subsequently developing<unk> . Other chemotherapy agents, including fludarabine, and topoisomerase II inhibitors are also associated with the development of<unk> ; most commonly after 4–6 years and 1–3 years respectively. These are often associated with specific chromosomal abnormalities in the leukemic cells. Other chemical exposures associated with the development of<unk>  include benzene, chloramphenicol and phenylbutazone. Radiation High amounts of ionizing radiation exposure, such as that used for radiotherapy used to treat some forms of cancer, can increase the risk of<unk> . People treated with ionizing radiation after treatment for prostate cancer, non-Hodgkin lymphoma, lung cancer, and breast cancer have the highest chance of acquiring<unk> , but this increased risk returns to the background risk observed in the general population after 12 years. Historically, survivors of the atomic bombings of Hiroshima and Nagasaki had an increased rate of<unk> , as did radiologists exposed to high levels of X-rays prior to the adoption of modern radiation safety practices. Genetics Most cases of<unk>  arise spontaneously, however there are some genetic mutations associated with an increased risk. Several congenital conditions increase the risk of leukemia; the most common is Down syndrome, with other more rare conditions including Fanconi anemia, Bloom syndrome and ataxia-telangiectasia (all characterised by problems with DNA repair), and Kostmann syndrome. Other factors Being overweight and obese increase the risk of developing<unk> , as does any amount of active smoking. For reasons that may relate to substance or radiation exposure, certain occupations have a higher rate of<unk> ; particularly work in the nuclear power industry, electronics or computer manufacturing, fishing and animal slaughtering and processing.
Acute myeloid leukemia
Acute lymphoblastic leukemia
Myeloid leukemia
Lymphoid leukemia
Prolymphocytic leukemia
Acute monocytic leukemia
Leukemoid reaction
T-cell leukemia