Hematopoiesis is the process of formation of new blood cells.1 During embryonic development, the process starts in the yolk sac, in so called blood islands. As development of the embryo progresses, blood cell formation continues predominantly in the liver, and after birth the bone marrow takes over the process of hematopoiesis. New blood cells continuously need to be generated throughout life, as the majority of mature blood cells have a limited life-span. In a healthy adult, this results in the estimated production of approximately 1010 new blood cells per hour.1 All different types of mature blood cells originate from a pool of self-renewing hematopoietic stem cells (HSC’s) that resides in the bone marrow. In a strictly regulated process, the multipotent HSC’s can differentiate into either a common myeloid or common lymphoid progenitor cells (Figure 1). While the lymphoid progenitor cells will differentiate and mature into either B-lymphocytes, T-lymphocytes, or natural killer cells, the myeloid progenitor cells will give rise to the other white blood cells (leukocytes) such as granulocytes (i.e. neutrophils, basophils and eosinophils), monocytes/macrophages and mast cells, but also to the red blood cells (erythrocytes) and the platelets (thrombocytes).

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Amgen, Genzyme, Novartis Oncology, Pediatric Oncology Foundation Rotterdam (KOCR)
R. Pieters (Rob)
Erasmus University Rotterdam
Erasmus MC: University Medical Center Rotterdam

Hollink, I. (2011, November 16). Molecular Genetic Insights in Cytogenetically-Normal Pediatric Acute Myeloid Leukemia. Retrieved from http://hdl.handle.net/1765/30660