In leukemia, the immature or abnormal cells that undergo uncontrolled expansion, resulting in an overproduction of these white blood cells and frequently, the inability to produce enough red blood cells and platelets. In the case of acute leukemias, the normal differentiation pathway is blocked at a stage where the cells are still proliferating but do not move into terminal differentiation. According to the 2018 GLOBOCAN survey, cases of leukemia are on the rise worldwide: 437,033 new cases of leukemia were registered with a global incidence rate of 5.2 and a mortality rate of 3.5 (ASR per 100,000).1 Based on the progenitor cell in the bone marrow, leukemia can be lymphocytic or myelocytic. Lymphocytic (lymphoblastic) leukemia arises from T or B lymphocytic progenitors whereas non-lymphocytic or myeloid leukemia arises from progenitors of erythrocytes, granulocytes, monocytes or platelets.1
What causes leukemia?
Leukemia is caused by genetic and metabolic alterations in lymphocyte or myeloid progenitors in the bone marrow. Environmental and lifestyle risks factors of leukemia include smoking, indoor and outdoor air pollution, exposure to radiation and certain chemicals, radiation therapy, chemotherapy and some genetic disorders such as Down Syndrome.2
Types of leukemia
Leukemia is categorized as acute or chronic based on the rate of proliferation of the leukemic cells. There are four major types of leukemia, two each for the predominant cell lineages—chronic/acute myeloid leukemia (CML and AML) and chronic/acute lymphocytic leukemia (CLL, ALL).3 Cases of cancer and leukemia are on the rise in the U.S. In 20 years (1998 to 2018) cases of all types of leukemia significantly increased to 187% for CLL, 108% for AML, 96% for CML and 92% for ALL.1,4
How is leukemia diagnosed?
Leukemia is a complex multifactorial disease and leukemia diagnosis requires an interdisciplinary approach, including review of symptoms and physical examination, blood tests, bone marrow biopsy, cerebrospinal fluid (CSF) evaluation, radiology, and genetic testing.
References
- Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries [published correction appears in CA Cancer J Clin. 2020 Jul;70(4):313]. CA Cancer J Clin. 2018;68(6):394-424. doi:10.3322/caac.21492
- Filippini T, Heck JE, Malagoli C, Del Giovane C, Vinceti M. A review and meta-analysis of outdoor air pollution and risk of childhood leukemia. J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2015;33(1):36-66. doi:10.1080/10590501.2015.100299
- Thapa B, Fazal S, Parsi M, Rogers HJ. Myeloproliferative Neoplasms. In: StatPearls. Treasure Island (FL): StatPearls Publishing; August 13, 2020.
- Hao T, Li-Talley M, Buck A, Chen W. An emerging trend of rapid increase of leukemia but not all cancers in the aging population in the United States. Sci Rep. 2019;9(1):12070. Published 2019 Aug 19. doi:10.1038/s41598-019-48445-1
