| 1. |
- Barosi, Giovanni, et al.
(author)
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Response criteria for essential thrombocythemia and polycythemia vera : result of a European LeukemiaNet consensus conference
- 2009
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In: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 113:20, s. 4829-4833
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Journal article (peer-reviewed)abstract
- European experts were convened to develop a definition of response to treatment in polycythemia vera (PV) and essential thrombocythemia (ET). Clinicohematologic (CH), molecular, and histologic response categories were selected. In ET, CH complete response (CR) was: platelet count less than or equal to 400 x 10(9)/L, no disease-related symptoms, normal spleen size, and white blood cell count less than or equal to 10 x 10(9)/L. Platelet count less than or equal to 600 x 10(9)/L or a decrease greater than 50% was partial response (PR). In PV, CH-CR was: hematocrit less than 45% without phlebotomy, platelet count less than or equal to 400 x 10(9)/L, white blood cell count less than or equal to 10 x 10(9)/L, and no disease-related symptoms. A hematocrit less than 45% without phlebotomy or response in 3 or more of the other criteria was defined as PR. In both ET and in PV, molecular CR was a reduction of any molecular abnormality to undetectable levels. Molecular PR was defined as a reduction more than or equal to 50% in patients with less than 50% mutant allele burden, or a reduction more than or equal to 25% in patients with more than 50% mutant allele burden. Bone marrow histologic response in ET was judged on megakaryocyte hyperplasia while on cellularity and reticulin fibrosis in PV. The combined use of these response definitions should help standardize the design and reporting of clinical studies.
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| 2. |
- Tefferi, Ayalew, et al.
(author)
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Proposals and rationale for revision of the World Health Organization diagnostic criteria for polycythemia vera, essential thrombocythemia, and primary myelofibrosis : recommendations from an ad hoc international expert panel
- 2007
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In: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 110:4, s. 1092-1097
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Journal article (peer-reviewed)abstract
- The Janus kinase 2 mutation, JAK2V617F, is myeloid neoplasm-specific; its presence excludes secondary polycythemia, or thrombocytosis or bone marrow fibrosis from other causes. Furthermore, JAK2V617F or a JAK2 exon 12 mutation is present in virtually all patients with polycythemia vera (PV) whereas JAK2V617F also occurs in approximately half of patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF). Therefore, JAK2 mutation screening holds the promise of a decisive diagnostic test in PV while being complementary to histology for the diagnosis of ET and PMF; the combination of molecular testing and histological review should also facilitate diagnosis of ET associated with borderline thrombocytosis. Accordingly, revision of the current World Health Organization (WHO) diagnostic criteria for PV, ET, and PMF is warranted; JAK2 mutation analysis should be listed as a major criterion for PV diagnosis and the platelet count threshold for ET diagnosis can be lowered from 600 to 450 x 109/L. The current document was prepared by an international expert panel of pathologists and clinical investigators in myeloproliferative disorders; it was subsequently presented to members of the Clinical Advisory Committee for the revision of the WHO Classification of Myeloid Neoplasms who endorsed the document and recommended its adoption by the WHO.
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