Evidence exists for the involvement of the most primitive and quiescent hematopoietic stem cell compartiment (CD34+/CD38-, Thy1+): t(9;22) is found in myeloid progenitor and in B-lymphocytes progenitors, but, involvement of the T-cell lineage is extremely rare. The existence of a highly quiescent stem cell population has been demonstrated in patients with CML. More recently, the presence of Ph ...

(Kdr), suggesting that they are hemangioblast precursors of the blood and vascular endothelial lineages. However, the preferential differentiation of PECAM positive vascular endothelial cells suggests that Pofut2 is essential for differentiation of the hematopoietic lineage. Many POFUT2 target proteins are constitutive components of ECM or associate with ECM. Among these, CCN, TSP, and ADAMTS f...

In multiple myeloma (MM), circulating endothelial cells (CECs) represent a vascular marker of angiogenesis and may reflect tumor mass. In this report, we showed that, in 5 MM patients with 13q14 deletion, CECs carried the same chromosome aberration as the neoplastic plasma cells (11%-32% of CECs with 13q14 deletion). Most of the CECs displayed immunophenotypic features of endothelial progenitor...

Embryonic stem cell-derived embryoid bodies contain a unique precursor population which, in response to vascular endothelial growth factor, gives rise to blast colonies in semi-solid medium. Upon transfer to liquid culture with appropriate cytokines, these blast colonies generate both hematopoietic and adherent, stromal-type cells. Cells within the adherent population display characteristics of...

Differentiation of pluripotent embryonic stem (ES) cells is associated with expression of fate-specifying gene products. Coordinated development, however, must involve modifying factors that enable differentiation and growth to adjust in response to local microenvironmental determinants. We report here that the ephrin receptor, EphB4, known to be spatially restricted in expression and critical ...

Mice deficient in the Flk-1 receptor tyrosine kinase are known to die in utero because of defective vascular and hematopoietic development. Here, we show that flk-1(-/-) embryonic stem cells are nevertheless able to differentiate into hematopoietic and endothelial cells in vitro, although they give rise to a greatly reduced number of blast colonies, a measure of hemangioblast potential. Further...

Hemangioblastomas are central nervous system (CNS) tumors of unknown histogenesis, which can occur sporadically or in von Hippel-Lindau disease. Hemangioblastomas are composed of neoplastic ‘‘stromal’’ cells of unknown origin, accompanied by intensive reactive angiogenesis. Failure to specify the cytologic origin of the stromal cell has precluded the development of nonsurgical therapies and lim...

The transcription factors Scl and Lmo2 are crucial for development of all blood. An important early requirement for Scl in endothelial development has also been revealed recently in zebrafish embryos, supporting previous findings in scl(-/-) embryoid bodies. Scl depletion culminates most notably in failure of dorsal aorta formation, potentially revealing a role in the formation of hemogenic end...