The international consensus classification of myeloid neoplasms and acute Leukemias: myeloproliferative neoplasms

Abstract

A group of international experts, including hematopathologists, oncologists, and geneticists were recently summoned (September 2021, Chicago, IL, USA) to update the 2016/17 World Health Organization classification system for hematopoietic tumors. After careful deliberation, the group introduced the new International Consensus Classification (ICC) for Myeloid Neoplasms and Acute Leukemias. This current in‐depth review focuses on the ICC‐2022 category of JAK2 mutation‐prevalent myeloproliferative neoplasms (MPNs): essential thrombocythemia, polycythemia vera, primary myelofibrosis, and MPN, unclassifiable. The ICC MPN subcommittee chose to preserve the primary role of bone marrow morphology in disease classification and diagnostics, while also acknowledging the complementary role of genetic markers for establishing clonality, facilitating MPN subtype designation, and disease prognostication.

Polycythemia vera: 2024 update on diagnosis, risk‐stratification, and management

“…Polycythemia vera (PV) is one of four JAK2 mutation‐prevalent myeloproliferative neoplasms (MPN), which also include essential thrombocythemia (ET), primary myelofibrosis (PMF), and MPN, unclassifiable (MPN‐U) 1–3 . In addition, about 15% of patients with PV or ET develop a PMF‐like phenotype, over time, referred to as post‐ET or post‐PV myelofibrosis 4 .…”

Momelotinib (JAK1/JAK2/ACVR1 inhibitor): mechanism of action, clinical trial reports, and therapeutic prospects beyond myelofibrosis

“…2 Morphologically, all three MPN variants display variable degrees of trilineage myeloproliferation associated with bone marrow stromal reaction that is most intense in MF, where abnormal megakaryocyte proliferation is often accompanied by bone marrow fibrosis, ineffective erythropoiesis (clinically apparent as anemia), aberrant cytokine expression (clinically apparent as constitutional symptoms and cachexia), and extramedullary hematopoiesis (EMH; clinically apparent as hepatosplenomegaly). 3 The three MPN variants also differ in disease course, survival outcome, and risk of progression into blast-phase disease (MPN-BP); reported median survivals for PMF, PV and ET were 4.4, 15, and 18 years, respectively, with corresponding leukemic transformation rates of 9.3%, 3.9%, and 2.6%. 4 Patients with MF are subject to not only premature death 4 but also poor quality-of-life (QoL).…”

International Consensus Classification for myeloid neoplasms at‐a‐glance

“…The ICC MPN subcommittee retained most of the structure and content from the 2016/17 WHO classification (revised 4th edition), in regard to the JAK2 mutation‐prevalent MPNs 2,8 . In CML, ICC recognizes three disease phases: chronic (CP), accelerated (AP), and blast (BP) phase 1 .…”

“…The most recent publication from the ICC‐2022 provides both basic and advanced information on molecular biology and elaborates on modern genomic diagnostics and risk stratification, as it relates to ICC‐assigned disease entities 7 . In the current editorial, which accompanies the first of a series of ICC‐2022 review articles that are slated to be published in the American Journal of Hematology , we highlight some of the changes in ICC‐2022, 8 compared to the 2016/17 WHO classification (revised 4th edition) 2 …”