Lineage Switching in Acute Leukemias: A Consequence of Stem Cell Plasticity?

Figure 1

Plasticity in the hematopoietic model. Hematopoietic system is organized as a hierarchy of cell types that gradually lose multiple alternate potentials while committing to lineage fates. Ectopic expression or loss of master transcription factors in committed or developing cells, as well as the cell response to microenvironmental cues such as growth factors and pathogen products, can change fate decisions and promote cell conversions. Blue arrows follow the normal hematopoietic model, whereas green arrows follow prospective pathways of plasticity. Red lines indicate differentiation blocking by effect of pathogens or TLR ligation. HSC: hematopoietic stem cells; MPP: multipotent progenitors; LMPP: lymphoid-primed multipotent progenitors; ELP: early lymphoid progenitors; CLP, common lymphoid progenitors; TLR: Toll-like receptors; MEP: megakaryocyte-erythroid progenitors; GMP: granulocyte-monocyte progenitors; Mac: macrophage; Gran: granulocytes; DC: dendritic cells; T, T cells; NK: natural killer cells; pDC: plasmacytoid dendritic cells; GM-CSFR: granulocyte-macrophage colony-stimulating factor receptor.