Myeloproliferative diseases and myelodysplastic syndromes

A 1951 editorial in Blood by William Dameshek [1], the editor of Blood and a Professor of Medicine at Tufts University, begins, “With accumulating experience, it becomes more and more evident that the bone marrow cells—erythroblasts, granulocytes, megakarycytes—often proliferate en masse or as a unit rather than as single elements.” He then proceeds to discuss chronic granulocytic leukemia, polycythemia vera, and myeloid metaplasia-myelofibrosis. There is no mention of essential thrombocythemia. This editorial preceded by 9 years the publications in Blood by Gunz [2] and in the American Journal of Medicine by Ozer et al [3] that put essential thrombocythemia on the map. Dameshek mentions that each of these three disorders has some features in common.

These observations preceded the development of a diagnostic triad for polycythemia vera [4], the demonstration by Adamson et al [5] that polycythemia vera is a clonal disorder, and the report by Nowell and Hungerford [6] of a chromosomal marker for chronic myeloid leukemia, the Philadelphia chromosome.

This also preceded our knowledge of stem cells, the concept of a pluripotent stem cell, and lineage-dependent stem cells. Erythrpoietin was known particularly from Reissmann's [7] study in parabiotic rats in 1950 (although it had been postulated by Carnot and DeFlandre in 1906 [8]), but the cytokines for granuloctytes and thrombocytes were not known.

Dameshek postulates that “they [chronic granulocytic leukemia, polycythemia vera, and myeloid metaplasia] are closely interrelated” and suggests that “these various conditions—“myeloproliferative disorders”—are all somewhat variable manifestations of proliferative activity of the bone marrow cells, perhaps due to a hitherto undiscovered stimulus.”

This issue of the Hematology/Oncology Clinics of North America brings together our current knowledge of the myeloproliferative disorders from the standpoint of their manifestation as clinical entities; presents a review of their pathology, molecular biology, and cytogenetics; examines the role of bone marrow transplantation; and offers predictions for the future.

This subject has not been presented as such in previous issues of the Hematology/Oncology Clinics of North America, although there was a 1992 issue on the myelodysplastic syndromes, whose relationship with the myeloproloiferative disorders is reviewed in this issue. Tifferi [9] edited a similarly titled issue of Seminars in Hematology in 1995; however, there is no overlap of contributors between that issue and this one. The goal of this issue is to give the reader a broad view of chronic myeloproliferative disorders.

I wish to acknowledge the contributions of Elaine Jaffe, John Bennet, Thomas Pearson, and Frank Gardner to the development of the contents and to each of the authors.