Meeting reportPrimary myelofibrosis (PMF), post polycythemia vera myelofibrosis (post-PV MF), post essential thrombocythemia myelofibrosis (post-ET MF), blast phase PMF (PMF-BP): Consensus on terminology by the international working group for myelofibrosis research and treatment (IWG-MRT)
Introduction
William Dameshek (1900–1969) is credited for introducing the term “myeloproliferative disorders (MPDs)”, in 1951 [1]. The original MPDs included chronic granulocytic leukemia (now known as chronic myelogenous/myeloid leukemia; CML), megakaryocytic leukemia/thrombocythemia (now known as essential thrombocythemia; ET), polycythemia vera (PV), and idiopathic or “agnogenic” myeloid metaplasia of the spleen (AMM) [1]. Among these disorders, the molecular basis of CML has since been characterized (BCR-ABL-positive) and the other three are now referred to as BCR-ABL-negative classic MPDs; a distinction that is now supported by the demonstration of an activating JAK2 mutation (JAK2V617F) in the majority of patients with BCR-ABL-negative classic MPDs [2]. The World Health Organization (WHO) classification system for hematologic malignancies identifies AMM as chronic idiopathic myelofibrosis (CIMF) [3], [4]. However, many other investigators in the field continue to use alternative names for the same disease (Table 1) and this lack of uniformity is also evident for the terms used to indicate the fibrotic transformation of PV or ET as well as the “leukemic” transformation of CIMF/AMM. Besides, the late Murray N. Silverstein (1928–1998) pointed out, in his classic monograph published in 1975, that CIMF/AMM might as well be called the “syndrome of pseudonyms” [5].
Section snippets
Background
The disease we identify as CIMF/AMM was first described in 1879 by Heuck who reported two cases he then called “splenic-medullary leukemia” and “pure splenic leukemia”, respectively [6]. Heuck noticed the ‘osteosclerosis’ in an autopsy report, a term later applied to the disease by Assman (1907) [7], and subsequently also described with advanced stage PV (1935) [8]. Similarly, the hepatosplenic extramedullary hematopoiesis (EMH) (1908) [9], [10], bone marrow fibrosis [10], and
Discussion points and recommendations
As recently underscored [13], it is difficult to incorporate the key blood, spleen, and bone marrow histological features of CIMF/AMM under one name. However, there has been substantial progress, in recent times, in understanding the pathogenesis of the disease [14]. First, it is now well established that CIMF/AMM represents myeloproliferation arising from an abnormal stem cell [15], [16]. Second, information from both experimental myelofibrosis in mice and cellular and plasma/bone marrow
Conclusion
The current recommendations by the IWG-MRT, regarding nomenclature for BCR-ABL-negative classic MPDs characterized by prominent myelofibrosis, were not designed to undermine either the value or the rationale behind currently existing nomenclature, but to establish internationally agreed upon terms. The working group admits that the proposed changes do not necessarily represent an “improvement”, but they embody, for the first time, a consensus from an international group of hematologists,
Acknowledgments
The current work is a summary of the proceedings from the second IWG-MRT meeting held in Houston, TX, USA, November 18, 2006. The meeting was jointly organized by the MD Anderson Cancer Center, Leukemia Department, and the Mayo Clinic, Myeloproliferative Disease Group. Supported by the Joe W. and Dorothy Dorsett Brown Foundation (Metairie, LA). A complete list of the IWG-MRT members and their affiliation is found in Appendix 1 of the manuscript.
References (32)
Some speculations on the myeloproliferative syndromes
Blood
(1951)- et al.
Classification of myeloproliferative disorders: from dameshek towards a semi-molecular system
Best Pract Res Clin Haematol
(2006) - et al.
Agnogenic myeloid metaplasia: a clonal proliferation of hematopoietic stem cells with secondary myelofibrosis
Blood
(1978) - et al.
Both B and T lymphocytes may be clonally involved in myelofibrosis with myeloid metaplasia
Blood
(2003) - et al.
Prominent role of TGF-beta 1 in thrombopoietin-induced myelofibrosis in mice
Blood
(2002) - et al.
Development of myelofibrosis in mice genetically impaired for GATA-1 expression (GATA-1(low) mice)
Blood
(2002) - et al.
Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders
Lancet
(2005) - et al.
Activating mutation in the tyrosine kinase JAK2 in polycythemia vera, essential thrombocythemia, and myeloid metaplasia with myelofibrosis
Cancer Cell
(2005) - et al.
MPL515 mutations in myeloproliferative and other myeloid disorders: a study of 1182 patients
Blood
(2006) - et al.
Clinical correlates of splenic histopathology and splenic karyotype in myelofibrosis with myeloid metaplasia
Blood
(2001)
Diagnostic and clinical relevance of the number of circulating CD34(+) cells in myelofibrosis with myeloid metaplasia
Blood
Hematopathologic findings in chronic idiopathic myelofibrosis
Semin Oncol
WHO histological classification of chronic myeloproliferative diseases
Chronic idiopathic myelofibrosis
Agnogenic myeloid metaplasia
Zwei Falle von Leukamie mit eigenthumlichem Blut-resp. Knochenmarksbefund (Two cases of leukemia with peculiar blood and bone marrow findings, respectively)
Arch Pathol Anat Physiol Virch
Cited by (255)
Comparison of Different Treatment Strategies for Blast-Phase Myeloproliferative Neoplasms
2022, Clinical Lymphoma, Myeloma and LeukemiaAccelerated and blast phase myeloproliferative neoplasms
2022, Best Practice and Research: Clinical HaematologyThrombosis in patients with post-polycythemia vera myelofibrosis: incidence and risk factors
2022, Thrombosis ResearchMutational landscape of blast phase myeloproliferative neoplasms (MPN-BP) and antecedent MPN
2022, International Review of Cell and Molecular BiologyCan molecular insights guide treatment of AML evolved from MPNs?
2021, Best Practice and Research: Clinical Haematology