**Hematopoietic Stem Cell in Acute Myeloid Leukemia Development**

Sérgio Paulo Bydlowski and Felipe de Lara Janz *University of Sao Paulo School of Medicine Laboratory of Genetics and Molecular Hematology, São Paulo, SP, Brazil* 

### **1. Introduction**

260 Advances in Hematopoietic Stem Cell Research

Yilmaz, O.H., Kiel, M.J., and Morrison, S.J. (2006). SLAM family markers are conserved

Zeggini, E., Scott, L.J., Saxena, R., Voight, B.F., Marchini, J.L., Hu, T., de Bakker, P.I.,

increase their purity. Blood *107*, 924-930.

loci for type 2 diabetes. Nat Genet *40*, 638-645.

among hematopoietic stem cells from old and reconstituted mice and markedly

Abecasis, G.R., Almgren, P., Andersen, G.*, et al.* (2008). Meta-analysis of genomewide association data and large-scale replication identifies additional susceptibility

> Hematopoietic stem cells (HSCs) are multipotent stem cells defined by their ability to selfrenewal, differentiation and maintenance of all blood cell types in the hematological system during the entire lifetime of the organism. This physiological process, called hematopoiesis, is controlled by several complex interactions between genetic processes in blood progenitor cells and bone marrow microenvironment. Hemostasis is maintained by a delicate balance between processes such as self-renewal, proliferation and differentiation versus apoptosis and cell-cycle arrest in HSCs. Over the last two decades, several studies have been made to understand possible mechanisms of cell malignancy and tumor growth, both in solid and hematological cancers. Leukemias are hematological malignancies that arise from cancer stem cells (CSCs). Neoplastic transformation of hematopoietic stem or progenitor cells occurs by unbalanced critical mechanisms. Blood cancers, as acute myeloid leukemia (AML), are sustained by leukemic stem cells (LSCs) which, like normal HSCs, present a range of biological characteristics that enable their long-term survival. AML is a well studied hematological cancer type characterized by an accumulation of clonal myeloid progenitor cells that do not differentiate normally. However, there is still no consensus about the mechanisms by which the HSCs transformation occurs. In this chapter, the hematopoietic stem cells and leukemic stem cells will be focused on leukemia development, mainly in AML.
