This meeting was convened by Richard T. Silver, M.D. and co-chaired by Jerry L. Spivak, M.D. It was held from 16 to 18 October 2003 in New York City, New York, USA. Thirty-nine invited speakers from nine different countries participated in the conference. There were more than 350 attendees. There were formal presentations and discussions on biology, clinical aspects, and management of patients with these diverse bone marrow stem cell disorders linked by a variable progression to acute myeloid leukemia. Of considerable interest, a clinical symposium exclusively for patients was held the day preceding the meeting at which John Bennett, Tiziano Barbui, Richard Silver, Jerry Spivak, and Ayalew Tefferi spoke on various topics pertaining to these diseases. This proved to be highly informative to the patients who reported that they enjoyed the program immensely. This was sponsored by the Cancer Research & Treatment Fund, Inc. Representatives of the Myelodysplasia Foundation were also present. This meeting report provides a summary of five different sections prepared by one or more of the session chairs. The keynote address was given by Shahin Rafii (Cornell Medical Center). Most appropriately, this talk focused on the expression and activation of angiogenic factors which play a crucial role in the progression of both myeloproliferative disorders and myelodysplastic syndromes (MDS). Among the known factors, vascular endothelial growth tyrosine kinase receptors (VEGF-R1, R2, and R3) support proliferation, survival, and mobility. Rafii's team has demonstrated that these receptors are expressed on subsets of primary hematopoietic cells as well as leukemic cells. Some leukemic cells express both VEGF-A and VEGF-R2, resulting in the generation of an autocrine loop that supports survival and within the osteoblastic zone translocating these cells to the vascular enriched niche for receipt of molecular instructions required for proliferation and differentiation. A pathologic correlation can be seen in some patients with the identification of abnormal localization of immature precursors (ALIP) in the central portions of the medullary cavity. Misplaced megakaryocytes can release pro-fibrotic factors, including platelet derived growth factors and transforming growth factor-beta. Collectively, these data suggest that chronic disregulation of angiogenic factors alter the microenvironment dislocating marrow stem cells that force both proliferation and differentiation in varying degrees, contributing to these hematological disorders.