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Harinder Gill Yok-Lam Kwong Editors
Pathogenesis and Treatment of Leukemia
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Pathogenesis and Treatment of Leukemia
Harinder Gill • Yok-Lam Kwong Editors
Pathogenesis and Treatment of Leukemia
Editors Harinder Gill Department of Medicine Queen Mary Hospital Hongkong, Hong Kong
Yok-Lam Kwong Department of Medicine Queen Mary Hospital Hongkong, Hong Kong
ISBN 978-981-99-3809-4 ISBN 978-981-99-3810-0 (eBook) https://doi.org/10.1007/978-981-99-3810-0 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023, corrected publication 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore
Contents
1 Basic Hematopoiesis and Leukemia Stem Cells������������������������������������������������������� 1 William Y. K. Hwang, Sudipto Bari, Lai Guan Ng, Koji Itahana, Shang Li, Javier Yu Peng Koh, and Hein Than 2 Modern Classification of Acute and Chronic Leukemias: Integrating Biology, Clinicopathologic Features, and Genomics����������������������������������������������� 13 Harinder Gill 3 Molecular Techniques in the Diagnosis and Monitoring of Acute and Chronic Leukaemias������������������������������������������������������������������������������������������� 23 Ho-Wan Ip and Wing-Fai Tang 4 Flow Cytometric Techniques in the Diagnosis and Monitoring of Acute Leukaemias��������������������������������������������������������������������������������������������������� 47 Melissa G. Ooi, Pak Ling Lui, Te Chih Liu, and Shir Ying Lee 5 Genomic Landscape and Risk Stratification of Acute Myeloid Leukemia����������� 61 Hsin-An Hou 6 Frontline Management of Acute Myeloid Leukaemia Eligible for Intensive Chemotherapy�������������������������������������������������������������������������������������� 91 Sudhir Tauro and Nigel H. Russell 7 Frontline Management of Elderly Acute Myeloid Leukemia Ineligible for Intensive Treatment ��������������������������������������������������������������������������������������������� 111 Yin-Jun Lou, Jie Jin, and Hong-Hu Zhu 8 Management of Acute Myeloid Leukemia with Myelodysplasia-Related Changes and Therapy-Related Acute Myeloid Leukemia��������������������������������������� 119 Jan Philipp Bewersdorf and Amer M. Zeidan 9 Management of Relapsed or Refractory AML��������������������������������������������������������� 129 Harinder Gill 10 The Role of BCL-2/MCL-1 Targeting in Acute Myeloid Leukemia����������������������� 133 Kenny Tang and Steven M. Chan 11 Role of IDH1/IDH2 Inhibitors in AML��������������������������������������������������������������������� 147 Harinder Gill 12 Next-Generation FLT3 Inhibitors for the Treatment of FLT3-Positive AML������� 151 Harinder Gill 13 Allogeneic Hematopoietic Stem Cell Transplantation for AML����������������������������� 159 Yu-Qian Sun and Xiao-Jun Huang 14 Maintenance Therapy Following Allogeneic Hematopoietic Stem Cell Transplantation in Acute Myeloid Leukemia����������������������������������������������������������� 167 Yong-Xian Hu and Hong-Hu Zhu v
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15 Immunotherapeutic Targeting of AML�������������������������������������������������������������������� 175 Ibraheem Motabi, Bader Alahmari, and John F. DiPersio 16 In the Pipeline: Emerging Therapy for Acute Myeloid Leukaemia����������������������� 193 Harinder Gill and Amber Yip 17 Frontline Management of Acute Promyelocytic Leukemia������������������������������������� 243 Harinder Gill 18 Management of Relapsed Acute Promyelocytic Leukemia and the Role of Hematopoietic Stem Cell Transplantation����������������������������������������������������������� 251 Harinder Gill 19 Genomic Landscape of Acute Lymphoblastic Leukemia (ALL): Insights to Leukemogenesis, Prognostications, and Treatment ����������������������������� 255 Sin Chun-fung 20 M anagement of Adolescent and Young Adults with Acute Lymphoblastic Leukaemia������������������������������������������������������������������������������������������������������������������� 277 Chi-Kong Li, Frankie Wai-Tsoi Cheng, and Daniel Ka-Leung Cheuk 21 Management of Older Patients with Acute Lymphoblastic Leukemia ����������������� 285 Xiao-Xia Hu and Hong-Hu Zhu 22 Management of Philadelphia Chromosome-positive Acute Lymphoblastic Leukaemia������������������������������������������������������������������������������������������������������������������� 289 Philip R. Selby, Kirsty M. Sharplin, Michael P. Osborn, and David T. Yeung 23 Management of Philadelphia Chromosome-Like Acute Lymphoblastic Leukemia (Ph-Like ALL)������������������������������������������������������������������������������������������� 311 Thai Hoa Tran and Sarah K. Tasian 24 Allogeneic Hematopoietic Stem Cell Transplantation for Acute Lymphoblastic Leukemia������������������������������������������������������������������������������������������� 329 Meng Lv, Wei Sun, and Xiao-Jun Huang 25 Immunotherapy for ALL������������������������������������������������������������������������������������������� 341 Wei Sun and Xiao-Jun Huang 26 In the Pipeline—Emerging Therapy for ALL ��������������������������������������������������������� 353 Harinder Gill, Cherry Chu, and Yammy Yung 27 Inherited/Genetic Predisposition to MDS and AML����������������������������������������������� 395 Lucy A. Godley 28 Clonal Hematopoiesis and Its Functional Implications in MDS/AML ����������������� 405 Harinder Gill 29 Therapy-Related MDS/AML and the Role of Environmental Factors����������������� 409 Maria Teresa Voso and Giulia Falconi 30 Prognostic Indicators in MDS and CMML ������������������������������������������������������������� 421 Harinder Gill, Yammy Yung, Cherry Chu, and Amber Yip 31 Treatment Algorithm of Myelodysplastic Syndromes��������������������������������������������� 437 Anne Sophie Kubasch and Uwe Platzbecker 32 Treatment Algorithm of CMML and Other Adult MDS/MPN Subtypes������������� 443 Florence Rabian and Raphael Itzykson
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33 Novel Strategies to Manage Cytopenia in Low-Risk MDS������������������������������������� 461 Valeria Santini 34 Allogeneic Hematopoietic Stem Cell Transplantation for MDS and CMML: When and How?��������������������������������������������������������������������������������������������������������� 469 Harinder Gill, Yammy Yung, Cherry Chu, and Amber Yip 35 In the Pipeline: Emerging Therapy for MDS and MDS/MPN������������������������������� 477 Harinder Gill, Emily Lee, and Pinky Mo 36 Molecular Landscape and Personalized Prognostic Prediction of MPNs������������� 501 Harinder Gill, Yammy Yung, Cherry Chu, and Amber Yip 37 Treatment Algorithm for Polycythemia Vera����������������������������������������������������������� 515 Jeanne Palmer and Ruben Mesa 38 Treatment Algorithm of Essential Thrombocythemia��������������������������������������������� 523 Jennifer O’Sullivan, Anna Green, and Claire Harrison 39 Prognostic Models for Primary and Secondary Myelofibrosis������������������������������� 539 Harinder Gill and Garret Leung 40 Treatment Algorithm for Primary and Secondary Myelofibrosis ������������������������� 543 Harinder Gill and Garret Leung 41 Diagnosis and Management of Prefibrotic Primary Myelofibrosis (Pre-PMF)������������������������������������������������������������������������������������������� 549 Tiziano Barbui, Alessandra Carobbio, and Jürgen Thiele 42 Interferons in Myeloproliferative Neoplasms����������������������������������������������������������� 559 Lucia Masarova and Srdan Verstovsek 43 JAK Inhibitors for the Management of Myeloproliferative Neoplasms ��������������� 567 Prithviraj Bose and Srdan Verstovsek 44 Allogeneic Hematopoietic Stem Cell Transplantation for Myelofibrosis: When and How?��������������������������������������������������������������������������������������������������������� 577 Nicolaus Kröger 45 Thrombosis and Myeloproliferative Neoplasms ����������������������������������������������������� 585 Alexandre Guy and Chloé James 46 Eosinophilic Disorders and Systemic Mastocytosis������������������������������������������������� 595 Harinder Gill, Yammy Yung, Cherry Chu, and Amber Yip 47 In the Pipeline: Emerging Therapy for Classical Ph-Negative MPNs������������������� 607 Harinder Gill and Yammy Yung 48 Current Guidelines and Treatment Algorithm of Chronic Myeloid Leukemia��������������������������������������������������������������������������������������������������������������������� 625 Carol Cheung Yuk Man 49 Treatment-Free Remission in Chronic Myeloid Leukemia������������������������������������� 635 Naranie Shanmuganathan and David M. Ross 50 Treatment Options in CML Resistant or Intolerant to Second-Generation Tyrosine Kinase Inhibitors����������������������������������������������������������������������������������������� 649 Carol Cheung Yuk Man
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51 Allogeneic Hematopoietic Cell Transplantation in CML: When and How?��������� 653 Fiona Fernando and Andrew J. Innes 52 In the Pipeline: Emerging Therapy for CML����������������������������������������������������������� 663 Harinder Gill, Emily Lee, and Pinky Mo Correction to: Molecular Techniques in the Diagnosis and Monitoring of Acute and Chronic Leukaemias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C1 Ho-Wan Ip and Wing-Fai Tang
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Basic Hematopoiesis and Leukemia Stem Cells William Y. K. Hwang, Sudipto Bari, Lai Guan Ng, Koji Itahana, Shang Li, Javier Yu Peng Koh, and Hein Than
Abstract
Keywords
There have been significant advances in the knowledge and understanding of hematopoiesis over the last century. Detailed functional, phenotypic, and genetic studies on hematopoietic stem and progenitor cells as well as cellular subsets have facilitated efforts in the diagnosis and prognostication of various diseases of the bone marrow. Identification of myriad cellular pathways has also facilitated the development of new drugs for the treatment of these diseases, especially for the blood cancers. Current development of novel techniques for the expansion and genetic modification of hematopoietic stem cells, mesenchymal stromal cells, and immune cells will further expand the toolbox for treating patients with otherwise fatal cancers and bone marrow diseases.
Hematopoiesis · Hematopoietic stem cells · Leukemia Bone marrow · Cord blood · Telomeres · Hematopoietic progenitors · Leukemia stem cells
W. Y. K. Hwang (*) National Cancer Centre Singapore, Singapore, Singapore Singapore General Hospital, Singapore, Singapore Duke-NUS Medical School, Singapore, Singapore e-mail: [email protected] S. Bari National Cancer Centre Singapore, Singapore, Singapore Duke-NUS Medical School, Singapore, Singapore Advanced Cell Therapy and Research Institute, Singapore, Singapore L. G. Ng National Cancer Centre Singapore, Singapore, Singapore A* Singapore Immunology Network (A* SIgN), Singapore, Singapore, Singapore K. Itahana · S. Li National Cancer Centre Singapore, Singapore, Singapore Duke-NUS Medical School, Singapore, Singapore J. Y. P. Koh Duke-NUS Medical School, Singapore, Singapore H. Than National Cancer Centre Singapore, Singapore, Singapore Singapore General Hospital, Singapore, Singapore
1.1 Introduction Hematopoiesis is essential for life in humans and most animals. Hematopoietic stem and progenitor cells (HSPCs) give rise to erythroid precursors which produce red blood cells (RBCs) that carry oxygen to tissues; myeloid precursors which produce cells that contribute mostly to the innate immune system; lymphoid precursors which produce cells that contribute to the adaptive immune system; and megakaryocyte precursors which produce platelets that help arrest bleeding. Due to its vital functions, HSPCs must begin function and production of progeny shortly after conception until death of the animal. In early human embryonic life, hematopoiesis begins briefly in the yolk sac, followed by its first definitive site in the aorto-gonado mesonephros from about 3 to 8 weeks of embryogenesis. Hematopoiesis then continues in the fetal liver (6 weeks to birth) and fetal spleen (10– 28 weeks) before transiting to the fetal bone marrow (18 weeks to adult life) [1]. At birth, some HSPCs may be harvested from the umbilical cord blood (UCB) and, subsequently, HSPCs may be harvested from the bone marrow (BM) or from the peripheral blood after mobilization (mPB). The discovery of hematopoietic cells and understanding of their function have progressed tremendously after the invention of the first compound microscope (inventor unknown) in 1620 [2]. Thereafter, the first description of RBCs was made by Jan Swammerdam in 1658 and later described in detail by Anthony van Leeuwenhoek in 1695. White blood cells (WBCs) were later discovered by Gabriel Andral and William Addison in 1843, while platelets and their function were discovered by Alfred Donne in 1842 [3], who also observed a maturation arrest of WBCs in some
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 H. Gill, Y.-L. Kwong (eds.), Pathogenesis and Treatment of Leukemia, https://doi.org/10.1007/978-981-99-3810-0_1
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patients. This was rapidly followed by publications by a series of authors who described “leucocythemia” in 1845, a reversed WBC and RBC balance called “leukämie” in 1847, and the first diagnosis of leukemia in a living patient using microscopy in 1946 [4]. Since then, treatments involving hematopoietic cells have advanced from primitive bloodletting practices to current safe and rational blood transfusions after the discovery of human blood groups by Karl Landstenier in 1900 [5]. The threat of nuclear warfare or radiation-induced BM failure led to a series of animal experiments including one, which showed that mice that received an infusion of BM cells from a syngeneic mouse could recover fully from total body irradiation [6]. This was followed by another study where mice which were given total body radiation to eradicate their leukemia followed by infusion of syngeneic marrow were able to recover hematopoiesis without leukemia relapse [7]. This was followed, shortly after, by the first HSC transplants (HSCTs) carried out using intensive radiation or chemotherapy to cure BM disease at the expense of normal hematopoiesis, followed by infusion of fresh BM cells to reconstitute the hematopoietic system [8]. While the first HSCTs were less successful, subsequent ones had resounding success with the use of immunosuppressive drugs and histocompatibility matching for donors. To date, over 1.5 million HSCTs have been performed for a variety of BM disorders and cancers with improving outcomes and extension of HSPC sources to include peripheral blood stem cells (PBSCs/mPB) and UCB [9, 10]. The scientific discoveries and cell processing techniques; as well as clinical infrastructure, expertise and workflow developed due to HSCTs have laid the foundation for modern day cell-based immunotherapy (for various cancers) and cell-based regenerative medicine (for aging-related diseases). New tools have emerged in the last few decades, which have rapidly enhanced our understanding of normal and abnormal hematopoiesis. These include methods from the last few decades which continue to be refined today, including multi-parametric flow cytometry for cell surface markers and polymerase chain reaction (PCR) techniques for nucleic acid studies. The last decade has seen further improvements in advanced techniques including whole genome sequencing, single cell gene analysis, genetic barcoding, cytometry by time-of-flight (CyTOF), and multiomic immune profiling. This book outlines many of the recent discoveries that have been made in the field of malignant hematopoiesis due to these technologies as well as the new therapies that have been made using small molecules, proteins, antibodies, and cells for the treatment of these diseases.
W. Y. K. Hwang et al.
1.2 Hematopoietic Stem and Progenitor Cells BM is the major site for hematopoiesis. The BM niche and its stromal cell components provide a specialized microenvironment for the maintenance of HSPCs, differentiation of lineage-restricted progenitor cells, and serve as a reservoir of mature leukocytes. It is well established that HSPCs can circulate between peripheral tissues after release from the BM [11, 12]. While the functional relevance of this phenomenon is not fully understood, it has been proposed that these tissue resident HSPCs are essential for extramedullary hematopoiesis. The classical model of hematopoiesis is defined by the hierarchical differentiation of HSPCs into common myeloid progenitors (CMP) and common lymphoid progenitors (CLP), which subsequently give rise to mature myeloid and lymphoid cells, respectively. While this hierarchical model has been instrumental for understanding the process involved in hematopoiesis, data generated from the single cell RNA sequencing (scRNA) technology have challenged this hematopoietic hierarchy. Specifically, these studies have provided evidence to show heterogeneity in the HSPCs population, forming the basis for a “continuum” differentiation model instead of a “concrete” step-wise differentiation model.
1.2.1 Hematopoietic Stem and Progenitor Cell Heterogeneity HSPCs are defined by their ability to repopulate the entire blood system after transplantation into lethally irradiated recipient/s. However, single cell and serial dilution transplantation studies have revealed significant difference in the engraftment activities and lineage-biased cell output. Moreover, single cell RNA (scRNA) analyses of HSPCs have also further confirmed the heterogeneity [13]. Of note, Wilson et al. have shown that there are two functionally distinct HSPC populations, i.e., repopulating HSPC and nonrepopulating HSPC in the transplantation model [14]. Additionally, HSPC subsets that are myeloid, lymphoid, and platelet-biased have also been reported [15]. Collectively, these data illustrate that HSPCs are heterogenous in terms of their molecular signature, as well as their function. It is important to point out that most of these studies focus on HSPC function in the context of transplantation. Thus, these results may not fully represent HSPC function during normal hematopoiesis. Indeed, in situ clonal tracking of HSPCs provided evidence to show that HSPCs have a minimal contribution to the mature leukocyte output, and that lineage-restricted progenitors are the cells driving steady state hematopoiesis [16, 17].
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1.2.2 Lineage Commitment from the Hematopoietic Stem and Progenitor Cell
markers such as CD38, CD135, CD45RA, CD110, and CD123 become highly expressed in the multiple subsets of CMP [19, 30]; while CD10 and CD7, along with CD34, are primarily used to identify the CLP that gives rise to mature T, One major feature of hematopoietic stem cells (HSCs) is B, and NK cells [31]. Viability being a key factor in detertheir ability to self-renewal. In contrast, hematopoietic pro- mining the quality of HSPCs is measured using dyes such as genitor cells (HPCs) lack the capability of extended self- 7-Aminoactinomycin D (7-AAD) [32] or 4′,6-diamidino-2renewal, and they are lineage-restricted—for example CLP phenylindole (DAPI) [33] in almost all multi-parametric and CMP. Lineage commitment decisions involve a series of flow cytometry panels. Cell cycle of HSPCs is yet another transcriptional events leading to lineage specification and key parameter to monitor, especially for those that are put in commitment. The classical model suggests that first lineage ex vivo cultures using propidium iodide (PI) staining, while commitment step is triggered by a strict bifurcation of HSC cell doubling is monitored through the use of carboxyfluointo CMP and CLP. However, there is growing evidence to rescein diacetate succinimidyl ester (CFSE) [34] or bromo- support the view that there is still plasticity in the lineage deoxyuridine (BrdU) [35] coupled with flow cytometer-based restriction of multipotential progenitors [18–20], indicating analysis. In clinical workflow, CD34 or CD133 antibodies that hematopoiesis does not follow a strict myeloid-lymphoid conjugated with magnetic nanoparticles are widely used for segregation as previously thought. Transcription factors play isolation and purification of HSPCs for therapeutic and diaga major role in lineage priming and commitment of multipo- nostic purposes [36]. Conventional morphology analysis tent cells. This is best exemplified by the cross-antagonism using hematoxylin and eosin (H&E) and May Grunwald- of transcription factors like GFI1 and IRF8, whereby the bal- Giemsa (MGG) stain is unable to allow specific recognition ance between these transcription factors is the major deter- of HSPCs as their appearance closely resembles small, mononuclear lymphocytes [37]. minant for neutrophil or macrophage fate choice [21].
1.3 Hematopoietic Stem and Progenitor Cell Assays The characterization and enumeration of HSPCs are essential in guiding both research and clinical workflows. The key tools used in assessing quality and quantity of HSPCs will be described in this section using phenotypic and functional assays.
1.3.1 Phenotypic Characterization Multi-parametric flow cytometry is a common tool that is used in research and clinical laboratories to perform immunotyping of HSPCs and various other lineages [22]. We are able to monitor the highly orchestrated process for hematopoiesis in blood and bone marrow samples using differentiation and self-renewal stage-specific markers that are expressed on HSPCs and its progenies. Almost all HSPCs express the pan-leucocyte marker, CD45, as well as the stem cell-specific glycoprotein, CD34, and exhibit low forward and side scatter (small cells) [23]. To date, expression of antigens such as CD90 [24], CD49f [25], CD133 [26], CD117 [27], and CD166 [28] have been shown to be present in long-term HSCs that concurrently lack expression of maturation markers such as CD45RA, CD38, and Lin [29]. With maturation of the HSCs to multipotent progenitors (MPPs), the expression of CD90, CD133, and CD49f is downregulated [23, 25]. Based on various studies lineage-specific
1.3.2 Colony Forming Unit (CFU) and Long- Term Culture-Initiating Cell (LT-CIC) Assays The discovery and implementation of the CFU assay for HSPCs have been pivotal in assessing the quality of the myeloid progenitor cells prior to therapeutic usage and to measure experimental outcomes [38]. In the CFU assay, a fixed number of input cells are cultured using a semisolid media supplemented with various hematopoietic-specific growth factors, which leads to the formation of myeloid progenitor-type-specific colonies [39]. The number and morphology of the colonies are used to determine the differentiation and proliferation capacity of the cultured progenitor cells [40]. In many instances, cells from the colonies can be harvested for further identification using flow cytometry and morphological analysis. CFU assays are appropriate for identification of progenitors that can give rise to granulocytic, erythroid, monocytic, and megakaryocytic lineages [41]. A major limitation of the CFU assay is its inability to assess the in vitro functional capacity of lymphoid progenitors. The LT-CIC assay is directed towards evaluating primitive hematopoietic progenitors, especially myeloid clonogenic progenitors [42], and has now been extended to quantification of lymphoid-lineage populations as well [43, 44]. In this assay, a feeder layer (e.g., M2-10B4) is generated following which HSPCs are added using serial dilution and those cultures are maintained greater than 5 weeks with
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appropriate media changes [42]. At end of the culture, CFU is plated using the harvested cells and generated colonies are scored. The data generated from LT-CIC assays enable to detect and quantitate primitive HSPCs that share phenotype and functionality with in vivo repopulating HSCs [45].
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studies for new types of cellular therapy grafts comprising of engineered or expanded human HSPCs, such animal studies are essential in establishing preclinical safety, efficacy, and lay the foundation for clinical protocols.
1.3.3 Xenotransplantation Studies
1.4 Hematopoietic Stem and Progenitor Cell Expansion
The long-term ability of human HSPCs to survive and give rise to multi-lineage, mature immune cells can only be assessed using xenotransplantation studies involving immunodeficient mice models. The most widely used mice strain is the nonobese diabetic (NOD) severe combined immunodeficiency (scid) gamma (NSG™) that are extremely immunodeficient and prevent host rejection of nonself- tissues [46, 47]. The NOD inbred background ensures impaired innate function; the Prkdcscid mutation prevents maturation of mouse T and B cells; and l2rgtm1Wjl mutation disrupts cytokine signalling and maturation of mouse NK cells [46, 47]. Furthermore, the unique allele of Sirpa along with myeloablative, sublethal total body irradiation (of up to 400 cGy) further enhances engraftment of human HSPCs in the NSG model [46, 47]. To date, there are over 40 variants of NSG™ mice, such as (i) NOD Rag gamma (NRG) mice that have similar capacity to engraft human HSPCs without the need to perform sublethal gamma irradiation [48]; (ii) NOD scid gamma Il3-GM-SF (NSG-SGM3) mice that have secretion of cytokines—IL-3, GM-CSF, and SCF in the BM niche which expedites myeloid lineage and regulatory T cell engraftment [49]; and (iii) NSG-IL15 mice that better support development of human NK cells [50]. A typical xenotransplantation study involves the following main steps: (i) pretransplantation preparatory activities that include antimicrobial drug prophylaxis (to prevent opportunistic infections); and myeloablation (to create space in the mouse BM niche); (ii) transplantation of the human HSPCs (purified CD34+ cells with or without mature immune cells) primarily via the intravenous route (tail vein injections); and (iii) posttransplantation follow-up that includes quantification of the human blood cells in the mouse peripheral blood (survival procedure); and BM and spleen (end of life procedures) primarily using flow cytometry [51]. In some cases, immunosuppressive drugs such as ciclosporin are administered to transplanted immunodeficient mice to alleviate symptoms of xeno-graft-versus-host-disease [52]. The NSG™ mice, once transplanted with CD34 expressing human HSPCs, start to show presence of human cells within 4–8 weeks posttransplantation and could remain alive for up to 12 months. In some instances, the human cells harvested from the BM of primary mice recipients are further transplanted to secondary immunodeficient mice to monitor the long-term self-renewal capacity of human HSPCs [25]. Prior to starting any clinical
HSCT has been effective in the cure of many hematological malignancies. In this clinical procedure, primary disease is treated by myeloablation of the BM followed by restoration of normal hematopoiesis through the infusion of healthy HSPCs from autologous or allogeneic sources. However, this 6-decade old procedure is associated with a significant period of post-conditioning pancytopenia as the infused HSPCs need to undergo engraftment, proliferation, and differentiation that lead to repopulation of the recipients’ BM and reestablishment of normal hematopoiesis [53]. Based on various studies, it has been established that the time to recovery is dependent on the quality and quantity of the HSPCs infused to the patients as well as the graft source (BM, mPB, or UCB) [54]. HSPC expansion that involves culturing cells in cGMP- grade cell therapy manufacturing facilities could help increase the infused cell dosage and improve the outcomes of both autologous and allogeneic HSCT by accelerating hematopoietic recovery [55]. However, while conventional hematopoietic cytokines such as stem cell factor (SCF), thrombopoietin (TPO), FMS-like tyrosine kinase 3 ligand (Flt-3L), and various interleukins (ILs) can promote the growth of late or committed progenitor cells (CMP and CLP) from HSCs, these cells lose long-term proliferative potential and become unusable as a HSCT graft that can impart life-long hematopoiesis [56]. Various efforts have been employed to expand hematopoietic progenitors while maintaining or enhancing long-lived HSCs. These include the use of novel cytokines or small molecules and mesenchymal stromal cell (MSC) coculture to mimic the innate microenvironment of the HSC niche in the BM [54]. Many of these studies have either shown no improvement in times to engraftment or failure of the expanded graft to contribute to long-term hematopoiesis. However, these studies have yielded important insights into the mechanisms of HSPC expansion, including the importance of maintenance of cell viability during ex vivo cultures [32, 57] and the presence of intercellular cytosolic and mitochondrial transfer during MSC coculture [58]. Recent studies involving the use of SR1 [59], UM171 [60], and nicotinamide [61] in ex vivo HSPC cultures have shown significant improvements in neutrophil and platelet engraftment times, while also maintaining long-term engraftment of the expanded cells. In a randomized phase 3 study of
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Omidubicel in cord blood transplantation using the nicotinamide platform, median time to neutrophil engraftment shortened from 22 to 12 days (p 16.5 g/ dL, Hct > 49%; women: Hb > 16 g/dL; Hct > 48%) Increased RBC mass (>25% above mean normal predicted value)
Platelet ≥450 × 109/L
BM biopsy showing megakaryocytic proliferation with atypiad; reticulin, and/or collagen fibrosis grade 2–3
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Presence of JAK2 V617F or JAK2 exon 12 mutatione
Presence of JAK2, CALR or MPL mutationf
BM biopsy showing megakaryocytic proliferation with atypiad; BM reticulin fibrosis grade 0–1; increased age-adjusted BM hypercellularity, granulocytic proliferation, and decreased erythropoiesis Presence of JAK2, CALR, or MPL mutationf; or Presence of another clonal markerg; or Absence of reactive BM fibrosish
Presence of JAK2, CALR, or MPL mutationf; or Presence of another clonal markerg; or Absence of reactive BM fibrosish
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Table 2.3 (continued) Criteria 3.
Minor 1.
PVa Age-adjusted BM hypercellularity with trilineage proliferation (panmyelosis) with pleomorphic mature megakaryocytes without atypia
ETb BM biopsy showing mainly megakaryocytic proliferation with increased number of large, mature megakaryocyte with hyperlobulated staghorn-like nuclei; infrequent dense clustersi; no significant increase or left-shift in granulopoiesis or increase in erythropoiesis; no significant marrow fibrosisj Diagnosed criteria for BCR::ABL1positive CML, PV, PMF, MDS, or other myeloid neoplasms are not met
prePMFc Diagnosed criteria for BCR::ABL1-positive CML, PV, ET, MDS, or other myeloid neoplasms are not met
Overt PMFc Diagnosed criteria for BCR::ABL1-positive CML, PV, ET, MDS or other myeloid neoplasms are not met
Subnormal EPO level
Presence of a clonal markerk or no evidence of reactive thrombocytosisl
Anemia not attributed to a comorbidities Leukocytosis ≥11 × 109/L
Anemia not attributed to a comorbidities Leukocytosis ≥11 × 109/L Palpable splenomegaly Elevated LDH LE blood picture
2. 3. 4. 5.
Palpable splenomegaly Elevated LDH
The diagnosis of PV requires either all three major criteria or the first two major criteria plus the minor criterion. A BM biopsy may not be required in patients with sustained absolute erythrocytosis (Men: Hb > 18.5 g/dL and Hct > 55.5%; Women: Hb > 16.5 g/dL and Hct > 49.5%) and the presence of JAK2V617F or JAK2 exon 12 mutation b The diagnosis of ET requires either all major criteria or the first three major criteria plus the minor criterion c The diagnosis of pre-PMF or overt PMF requires all three major criteria and at least one minor criterion confirmed in two consecutive assessments d Megakaryocytic atypia is a distinctive feature of pre-PMF and overt PMF. Features include variation in size from small to giant megakaryocytes and severe maturation defects (cloud-like, hypolobulated, and hyperchromatic nuclei) and the presence of abnormally large and dense clusters (>6 megakaryocytes lying strictly adjacent) e A highly sensitive assay for JAK2V617F (sensitivity 5 cm increase in palpable splenomegaly from baseline or new development of palpable splenomegaly Development of 2 or more of the following symptoms: >10% weight loss in 6 months; night sweats; unexplained fever (>37.5 °C)
Anemia and >2 g/dL reduction in Hb from baseline LE blood picture >5 cm increase in palpable splenomegaly from baseline or new development of palpable splenomegaly Elevated LDH
Development of 2 or more of the following symptoms: >10% weight loss in 6 months; night sweats; unexplained fever (>37.5 °C)
The diagnosis of post-PV MF or post-ET MF is established with the presence of all required criteria and at least two additional criteria
16
H. Gill
2.3 Myeloid/Lymphoid Neoplasms with Eosinophilia and Tyrosine Kinase Gene Fusions (MLN-TK) MLN-TK are currently defined as myeloid or lymphoid neoplasms driven by specific gene fusions that activate
receptor tyrosine kinases [2, 3]. They are commonly associated with eosinophilia. Common associated gene fusions, clinical associations, and their therapeutic implications are shown in Table 2.5 [2, 3]. Of note, MLN-TK must be excluded before the diagnosis of CEL, mastocytosis, or HES is made.
Table 2.5 Genomic and clinical characteristics of myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions [2, 3, 17–21] Gene PDGFRA PDGFRB FGFR1 JAK2 FLT3
ABL1
Commonest gene fusions FIP1L1::PDGFRA/cryptic 4q12 deletion ETV6::PDGFRB/t(5;12) (q32;p13) ZMYM2::FGFR1/t(8;13) (p11.2;q12.1) PCM1::JAK2/t(8;9) (p22;p24.1) ETV6::FLT3/t(12;13) (p13.2;q12.2) ETV6::ABL1/t(9;12) (q34.1;p13.2)
Other fusion partners CDK5RAP2, STRN, KIF5B, TNKS2 ETV6, BCR >30 other partners 15 other partners ETV6, BCR ZMYM2, TRIP11, SPTBN1, GOLGB1, CCDC88C, MYO18A, BCR –
Clinical features Eosinophilia +/− end-organ damage Eosinophilia +/− end-organ damage, and monocytosis T-ALL/LL with eosinophilia or BM showing MPN in blast phase MPN or MDS/MPN with eosinophilia T-ALL/LL or myeloid sarcoma with eosinophilia or BM MDS/ MPN features MPN with eosinophilia
Treatment implications Responsive to imatinib Responsive to imatinib Responsive to FGFR inhibitor Variable responses to ruxolitinib Variable response to FLT3 inhibitors Variable responses to dasatinib/nilotinib
T-ALL/LL T-acute lymphoblastic leukemia/lymphoblastic lymphoma, BM bone marrow, MDS myelodysplastic syndrome, MPN myeloproliferative neoplasm; +/− with or without, FGFR fibroblast growth factor receptor, IFN-α interferon-alfa
2 Modern Classification of Acute and Chronic Leukemias: Integrating Biology, Clinicopathologic Features, and Genomics
2.4 Mastocytosis Mastocytosis is a group of rare heterogeneous hematologic neoplasms characterized by the accumulation of morphologically abnormal mast cells in the bone marrow, organs, or tissues. The 2022 WHO classification recognizes three major subtypes of mastocytosis: cutaneous mastocytosis, systemic mastocytosis, and mast cell sarcoma [3]. Subtypes of systemic mastocytosis comprise bone marrow mastocytosis, indolent systemic mastocytosis, smoldering systemic mastocytosis, aggressive systemic mastocytosis, and systemic mastocytosis with an associated hematologic neoplasm (SM-AHN) [3]. Somatic KIT mutations at codon 816 are present in more than 90% of patients with systemic mastocytosis, while rare mutations in the extracellular or juxtamembrane are present in less than 1% [3]. Co-occurring mutations in TET2, SRSF2, ASXL1, RUNX1, and JAK2 are frequently present in SM-AHM [3, 22]. Patients with somatic KIT mutations may respond to treatment with the tyrosine kinase inhibitor midostaurin [23, 24].
2.5 Myelodysplastic/Myeloproliferative Neoplasms The major subtypes of myelodysplastic/myeloproliferative neoplasm (MDS/MPN) under the WHO 2022 classification comprise chronic myelomonocytic leukemia (CMML), MDS/MPN with neutrophilia (formerly atypical chronic myeloid leukemia), MDS/MPN with SF3B1 mutation and thrombocytosis (formerly MDS/MPN with ring sideroblasts and thrombocytosis), and MDS/MPN not otherwise specified [3]. The diagnostic criteria for CMML have been refined (Table 2.6) most notably with the lower threshold for absolute monocytosis to 0.5 × 109/L and the elimination of the category CMML-0 [3]. The designation of CMML-0 lacks prognostic significance and was thus removed. Somatic mutations are detected in more than 90% of patients with CMML, most frequently in SRSF2, TET2, and ASXL1 [25, 26]. Other somatic mutations that are associated with CMML involve the genes SETBP1, NRAS/KRAS, RUNX1, CBL, and EZH2 [3, 25, 26]. MDS/MPN with neutrophilia or atypical chronic myeloid leukemia (aCML) is characterized by WBC ≥ 13 × 109/L (with ≥10% neutrophils and their precursors), cytopenia, blasts