Role of HOX Genes in Stem Cell Differentiation and Cancer

Figure 2

HOX gene expression during hematopoiesis. The hematopoietic stem cell (HSC) is a multipotent stem cell that has the ability to give rise to common lymphoid progenitor (CLP) and common myeloid progenitor (CMP) cells. HOXA9, HOXB4, and HOXB6 are known to be expressed in HSC and regulate HSC self-renewal. HOXA5 and HOXA9 are involved in the proliferation and differentiation of HSC to CMP, and HOXA9 regulates the differentiation of HSC into CLP. HOXB3 is expressed during the differentiation of pre-B cells into B cells. HOXA5 and HOXC8 are expressed during erythroid differentiation of megakaryocyte-erythrocyte progenitors (MEP) whereas HOXA7 is expressed during megakaryocyte differentiation. HOXC3 and HOXC4 are crucial during erythroid lineage differentiation. HOXC8 is shown to play a regulatory role during the differentiation of granulocyte-monocyte progenitor (GMP) cells. HSC: hematopoietic stem cells; CMP: common myeloid progenitor; CLP: common lymphoid progenitor; MEP: megakaryocyte-erythrocyte progenitor; GMP: granulocyte-monocyte progenitor; BFU-E: erythroid burst-forming units; CFU-E: erythroid colony-forming unit; CFU-Meg: megakaryocyte colony-forming unit; CFU-mast: mast colony-forming unit; CFU-Eo: eosinophil colony-forming unit; CFU-GM: granulocyte-monocyte colony-forming unit; CFU-Oc: osteoclasts colony-forming unit.