Molecular and functional characterization of early human hematopoiesis.

Through improvements in xenograft assay methods and in the identification of novel cell surface markers, significant progress has been made in our understanding of the human hematopoietic stem and progenitor hierarchy. The isolation of clonally pure populations of stem cells and early progenitors opens the way to carry out gene expression profiling studies to uncover the molecular regulators of each developmental step and to gain insight into the process of lineage commitment in human hematopoiesis.