ReviewA clinical update in polycythemia vera and essential thrombocythemia
Section snippets
Pathogenesis
Several studies have shown that the clonal process in polycythemia vera originates in stem cells (5). The underlying molecular lesion has not been identified. Recent studies have focused on the mechanisms responsible for the proliferation and survival of red blood cells independent of erythropoietin (6). Structural or functional alterations of the erythropoietin receptor or its corresponding downstream effectors have not been detected 7, 8. The erythropoietin-independent viability of red blood
Pathogenesis
X-linked enzyme or genetic analysis has suggested that patients with essential thrombocythemia have clonal hematopoiesis that originates in stem cells 31, 32. However, the issue of clonality is complicated by the recent demonstration of monoclonal hematopoiesis in normal elderly women (33) and polyclonal hematopoiesis in some patients with essential thrombocythemia (34).
It is not certain if there is a pathogenetic link between clonal thrombocytosis and thrombopoietin. In patients with essential
Is hydroxyurea leukemogenic?
Polycythemia vera and essential thrombocythemia are clonal disorders with an inherent tendency to evolve into acute myeloid leukemia 3, 53. Because they are not genetically defined, biologic heterogeneity could exist within each disease group, and this may affect the risk of developing leukemia. In addition, longer duration of disease and evolution into myelofibrosis increase the risk of leukemic transformation 3, 54. Therefore, patient selection may influence observed rates of leukemic
Conclusion
Treatment strategies for patients with polycythemia vera or essential thrombocythemia are based primarily on the presence or absence of risk factors for thrombohemorrhagic complications Table 4, Table 5, Table 6. Treatment may require modification in women who are, or plan to become, pregnant.
Low-risk patients may fare better without any cytoreductive therapy 3, 47, and the use of low-dose aspirin in these patients is optional 28, 81. Although there is no good evidence that drug therapy
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The JAK2 mutation
2021, International Review of Cell and Molecular BiologyCitation Excerpt :Essential thrombocythemia (ET), previously described as “hemorrhagic thrombocythemia”, is characterized by the proliferation of megakaryocytes in bone marrow and thrombocytosis in peripheral blood without association with erythrocytosis and leucoerythroblastosis. Megakaryocytes feature hyperlobated nuclei, and megakaryocyte precursors are hypersensitive to several cytokines, including thrombopoietin, IL-3, and IL-6 (Li et al., 1994; Tefferi et al., 2000). ET can occur as a clonally heterogeneous disease, and sometimes clonality is only restricted to megakaryocytic lineage (el Kassar et al., 1995; Harrison et al., 1999).
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2012, Platelets, Third EditionChronic Myeloproliferative Disorders
2010, Current Clinical Medicine: Expert Consult Premium Edition - Enhanced Online Features and Print
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Dr. Silverstein was involved in the initial preparation of this manuscript. He died on September 15, 1998.