scholarly journals The Origin of B-cells: Human Fetal B Cell Development and Implications for the Pathogenesis of Childhood Acute Lymphoblastic Leukemia

2021 ◽  
Vol 12 ◽  
Author(s):  
Thomas R. Jackson ◽  
Rebecca E. Ling ◽  
Anindita Roy
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
B Cells ◽  
B Cell ◽  
Lymphoblastic Leukemia ◽  
In Utero ◽  
Cell Development ◽  
B Cell Development ◽  
Postnatal Life ◽  
B Lymphopoiesis ◽  
B Lymphoid

Human B-lymphopoiesis is a dynamic life-long process that starts in utero by around six post-conception weeks. A detailed understanding of human fetal B-lymphopoiesis and how it changes in postnatal life is vital for building a complete picture of normal B-lymphoid development through ontogeny, and its relevance in disease. B-cell acute lymphoblastic leukemia (B-ALL) is one of the most common cancers in children, with many of the leukemia-initiating events originating in utero. It is likely that the biology of B-ALL, including leukemia initiation, maintenance and progression depends on the developmental stage and type of B-lymphoid cell in which it originates. This is particularly important for early life leukemias, where specific characteristics of fetal B-cells might be key to determining how the disease behaves, including response to treatment. These cellular, molecular and/or epigenetic features are likely to change with age in a cell intrinsic and/or microenvironment directed manner. Most of our understanding of fetal B-lymphopoiesis has been based on murine data, but many recent studies have focussed on characterizing human fetal B-cell development, including functional and molecular assays at a single cell level. In this mini-review we will give a short overview of the recent advances in the understanding of human fetal B-lymphopoiesis, including its relevance to infant/childhood leukemia, and highlight future questions in the field.

Precursor B Cell Acute Lymphoblastic Leukemia Induces Pro-Leukemic Changes in the Bone Marrow Microenvironment That Contribute to Therapeutic Resistance

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1466-1466
Author(s):  
Christopher D Chien ◽  
Elizabeth D Hicks ◽  
Paul P Su ◽  
Haiying Qin ◽  
Terry J Fry
Keyword(s):  
Bone Marrow ◽  
Acute Lymphoblastic Leukemia ◽  
B Cells ◽  
B Cell ◽  
Lymphoblastic Leukemia ◽  
Cell Development ◽  
B Cell Development ◽  
Bone Marrow Microenvironment ◽  
Therapeutic Resistance

Abstract Abstract 1466 Pediatric acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. Although cure rates for this disease are approximately 90%, ALL remains one of the leading causes cancer-related deaths in children. Thus, new treatments are needed for those patients that do not respond to or recur following standard chemotherapy. Understanding the mechanisms underlying resistance of pediatric ALL to therapy offers one approach to improving outcomes. Recent studies have demonstrated the importance of communication between cancer cells and their microenvironment and how this contributes to the progression and therapeutic resistance but this has not been well studied in the context of ALL. Since the bone marrow is presumed to be the site of initiation of B precursor ALL we set out in our study to determine how ALL cells utilize the bone marrow milieu in a syngeneic transplantable model of preB cell ALL in immunocompetent mice. In this model, intravenously injected preB ALL develops first in the bone marrow, followed by infiltration into the spleen, lymph node, and liver. Using flow cytometry to detect the CD45.2 isoform following injection into B6CD45.1+ congenic recipients, leukemic cells can be identified in the bone marrow as early as 5 days after IV injection with a sensitivity of 0.01%-0.1%. The pre-B ALL line is B220+/CD19+/CD43+/BP1+/IL-7Ralpha (CD127)+/CD25-/Surface IgM-/cytoplasmic IgM+ consistent with a pre-pro B cell phenotype. We find that increasing amounts of leukemic infiltration in the bone marrow leads to an accumulation of non-malignant developing B cells at stages immediately prior to the pre-pro B cell (CD43+BP1-CD25-) and a reduction in non-malignant developing pre B cells at the developmental stage just after to the pre-pro B cell stage (CD43+BP1+CD25+). These data potentially suggest occupancy of normal B cell developmental niches by leukemia resulting in block in normal B cell development. Further supporting this hypothesis, we find significant reduction in early progression of ALL in aged (10–12 month old) mice known to have a deficiency in B cell developmental niches. We next explored whether specific factors that support normal B cell development can contribute to progression of precursor B cell leukemia. The normal B cell niche has only recently been characterized and the specific contribution of this niche to early ALL progression has not been extensively studied. Using a candidate approach, we examined the role of specific cytokines such as Interleukin-7 (IL-7) and thymic stromal lymphopoietin (TSLP) in early ALL progression. Our preB ALL line expresses high levels of IL-7Ralpha and low but detectable levels of TLSPR. In the presence of IL-7 (0.1 ng/ml) and TSLP (50 ng/ml) phosphSTAT5 is detectable indicating that these receptors are functional but that supraphysiologic levels of TSLP are required. Consistent with the importance of IL-7 in leukemia progression, preliminary data demonstrates reduced lethality of pr-B cell ALL in IL-7 deficient mice. Overexpression of TSLP receptor (TSLPR) has been associated with high rates of relapse and poor overall survival in precursor B cell ALL. We are currently generating a TSLPR overepressing preBALL line to determine the effect on early ALL progression and are using GFP-expressing preB ALL cells to identify the initial location of preB ALL occupancy in the bone marrow. In conclusion, or model of early ALL progression provides insight into the role of the bone marrow microenvironment in early ALL progression and provides an opportunity to examine how these microenvironmental factors contribute to therapeutic resistance. Given recent advances in immunotherapy for hematologic malignancies, the ability to study this in an immunocompetent host will be critical. Disclosures: No relevant conflicts of interest to declare.

Haploinsufficiency of Ebf1 Collaborates with BCR-ABL1 to Decrease the Latency of Acute Lymphoblastic Leukemia.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3363-3363
Author(s):  
Salil Goorha ◽  
Noel T. Lenny ◽  
Christopher B Miller ◽  
S. Scott Perry ◽  
Xiaoping Su ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Lymphoblastic Leukemia ◽  
B Cells ◽  
B Cell ◽  
Copy Number ◽  
Lymphoblastic Leukemia ◽  
B Cell Development ◽  
B Lineage ◽  
B Lymphoid

Abstract In previously published genome-wide copy number analysis of leukemic samples from 242 pediatric acute lymphoblastic leukemia (ALL) patients, we reported that mutations in genes regulating B lymphoid development are the most common lesion in B-progenitor ALL, and these include PAX5, IKZF1, and EBF1. Mono-allelic deletion of EBF1 was observed in 8/200 B-progenitor leukemia samples, including a BCR-ABL1 ALL. EBF1 encodes a transcription factor that is required for the development of B cells, and with E2A regulates the expression of B-lineage specific genes. Mice null for Ebf1 arrest B cell development at the pro-B cell stage, whereas Ebf1+/− mice have a 50% reduction in the number of immature and mature B cells but a normal number of pro-B cells. Importantly, neither haploinsufficiency nor the complete loss of Ebf1 results in the development of leukemia in mice. To examine the role of genetic alterations targeting B-lymphoid differentiation in the pathogenesis in BCR-ABL1 ALL, we transduced Ebf1+/+ and Ebf1+/− bone marrow cells with MSCV-GFP-IRES-p185 BCR-ABL1 retrovirus and transplanted the resultant cells into lethally irradiated wild-type C57BL6 recipient mice. Mice transplanted with BCR-ABL1 Ebf1+/− cells developed B lineage ALLs at a shorter latency than observed with BCR-ABL1 Ebf1+/+ cells (median overall survival of 17 days in Ebf1+/− vs 42 days in Ebf1+/+, P<0.0001). All leukemias had a B220+Cd19+Bp1+ pre-B cell immunophenotype; however, the leukemias that developed from the Ebf1+/− cells aberrantly expressed high levels of the stem cell marker Sca1 (mean fluorescence level for Sca1 of 69.6 in Ebf1+/− (n=22) vs 16.8 in Ebf1+/+ (n=14), p<0.0001). To begin to understand how a decrease in the copy number of Ebf1 may contribute to leukemogenesis, we examined early B cell development in bone marrow (BM) cells from two week-old C57BL6 Ebf1+/− and Ebf1+/+ mice. Our analysis confirmed previous reports indicating a 2-fold reduction of B220+CD43− B cells in Ebf1+/− compared to Ebf1+/+ mice. Interestingly, however, we also detected an approximately 6-fold increase in a transitional population of B220loIL-7R+cKitlo Pre-pro B cells that also expressed Sca1 (2194 mean number of Ebf1+/− cells per 100,000 BM cells (n=10) vs 372 mean number of Ebf1+/+ cells per 100,000 BM cells (n=8), p<0.0001), an observation that raises the possibility that Ebf1 haploinsufficiency expands the pool of cells that are susceptible to transformation by BCR-ABL expression. It will be important to examine whether the accelerated tumorigenesis resulting from Ebf1 haploinsufficiency is a consequence of a subtle shift in differentiation, or some alternative mechanism of oncogenic cooperativity. Studies are underway to directly assess the role of B220loIL-7R+cKitlo Sca1+ cells in BCR-ABL1 driven ALL.

scholarly journals Extensive RAG-Mediated Rearrangements and Mutations in BCR-ABL1 and BCR-ABL1-like Adult Acute Lymphoblastic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4067-4067
Author(s):  
Mathijs A. Sanders ◽  
Anikó Szabó ◽  
Carla Exalto ◽  
Remco Hoogenboezem ◽  
Annelieke Zeilemaker ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
B Cells ◽  
B Cell ◽  
De Novo ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Genetic Alterations ◽  
Cell Development ◽  
B Cell Development ◽  
Genetic Events

Abstract BCR-ABL1 and BCR-ABL1-like acute lymphoblastic leukemia (ALL) are two major pre-B cell acute leukemia subtypes characterized by genetic alterations affecting lymphoid-specific transcription factors. Studies examining the chain of genetic events necessary to develop leukemia established that the BCR-ABL1 fusion gene and kinase-activating BCR-ABL1-like lesions are initiating events, however, insufficient for leukemia development. Secondary genetic events targeting B cell development genes are therefore an essential requirement for overt ALL. A recent study (Papaemmanuil et al, Nat. Genet., 2014) revealed that illegitimate RAG-mediated recombination is the predominant mutational mechanism establishing these secondary genetic events in ETV6-RUNX1 ALL. Of note, ETV6-RUNX1ALL is mainly restricted to pediatric cases and it remains unanswered whether this mutational process also plays a prominent role in adult ALL pathogenesis. We carried out a detailed genomic characterization to determine whether aberrant RAG activity is also a prominent mutational driver in certain adult B cell ALL (B-ALL) subtypes. Diagnostic material of 53 unselected B-ALL cases and matched remission specimens were characterized using DNA mapping arrays to discern copy number alterations (CNAs). We observed multiple BCR-ABL1/BCR-ABL1-like patients with abundant genetic lesions and selected 5 cases for targeted sequencing of CNA boundaries to determine whether these lesions were driven by RAG-mediated recombination. Whole genome sequencing (WGS) for a single BCR-ABL1-like patient was used to asses this mutational mechanism genome-wide. In total 64 structural variants (SVs) could be analyzed at base-pair level. De novo motif detection on breakpoint sequences revealed the prominence of the heptamer CACAGTG (E-value=5.68x10-91), a constituent of the recombination signal sequence (RSS), present in 121 out of 128 breakpoints (94.5%). RSS detection revealed that 58 out of 64 SVs (90.6%) had a cryptic RSS (cRSS) on one or both sides of the lesion. Incorporation of non-templated sequences was observed for 54 out of the 64 (84.4%) SVs. Superimposition of breakpoints on chromatin marks revealed a strong enrichment for active promoters and enhancers (p < 2.2x10-16). WGS data revealed cRSS motifs and incorporation of non-templated sequences for 23 out of 26 SVs (88.5%). Integrative analysis of all 6 cases confirmed 125 unique SV breakpoints strongly enriched for the active chromatin marks H3K4me3 and H3K27ac. STAT5 binding, a postulated regulator of V(D)J recombination, is similarly enriched at the breakpoints. Promiscuous binding of RAG1 and RAG2 was previously noted in human thymocytes and murine pre-B cells (Teng et al, Cell, 2015). Strikingly, the breakpoints are frequently bound by RAG2 in human thymocytes. In total 66 out of 125 breakpoints could be translated to the murine genome and revealed a strong enrichment of RAG1 and RAG2 binding at homologous positions in murine pre-B cells. Exhaustive mutation detection revealed complex somatic mutations within cRSS motifs, which are rare V(D)J recombination products introduced by erroneous cleavage and error-prone repair (open-and-shut joints). Strikingly, 4 out of 6 BCR-ABL1/BCR-ABL1-like cases had mutations in the BTLA promoter-situated cRSS, frequently in combination with a RAG-mediated deletion of the other allele (Figure 1). Genomic screening in 142 B-ALL patients confirmed 8 additional cases with BTLA promoter mutations, predominantly (6 out of 8) belonging to the BCR-ABL1/BCR-ABL1-like subgroups. We provide strong evidence that aberrant RAG activity plays a pivotal role in the development of BCR-ABL1/BCR-ABL1-like adult ALL. We demonstrate that breakpoints are strongly enriched for RAG binding implying a predisposition for illegitimate V(D)J recombination. Importantly, we report on a novel mutational mechanism introducing mutations in cRSS motifs through open-and-shut joints, frequently resulting in the biallelic inactivation of BTLA. Proliferation and V(D)J recombination during pre-B cell development is orchestrated by the interplay of IL7R and pre-BCR signalling. Strikingly, most kinase-activating lesions constitutively activate these signalling cascades and could enact, in concert with BTLA inactivation, constant proliferation, pro-survival and V(D)J recombination-initiating signals with disastrous consequences. Disclosures No relevant conflicts of interest to declare.

scholarly journals Ligand-independent Signaling Functions for the B Lymphocyte Antigen Receptor and Their Role in Positive Selection during B Lymphopoiesis

2001 ◽  
Vol 194 (11) ◽  
pp. 1583-1596 ◽  
Author(s):  
Gregory Bannish ◽  
Ezequiel M. Fuentes-Pananá ◽  
John C. Cambier ◽  
Warren S. Pear ◽  
John G. Monroe
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocyte ◽  
Antigen Receptor ◽  
Cell Development ◽  
B Cell Development ◽  
B Lymphopoiesis ◽  
Biologically Relevant ◽  
Developmental Progression

Signal transduction through the B cell antigen receptor (BCR) is determined by a balance of positive and negative regulators. This balance is shifted by aggregation that results from binding to extracellular ligand. Aggregation of the BCR is necessary for eliciting negative selection or activation by BCR-expressing B cells. However, ligand-independent signaling through intermediate and mature forms of the BCR has been postulated to regulate B cell development and peripheral homeostasis. To address the importance of ligand-independent BCR signaling functions and their regulation during B cell development, we have designed a model that allows us to isolate the basal signaling functions of immunoglobulin (Ig)α/Igβ-containing BCR complexes from those that are dependent upon ligand-mediated aggregation. In vivo, we find that basal signaling is sufficient to facilitate pro-B → pre-B cell transition and to generate immature/mature peripheral B cells. The ability to generate basal signals and to drive developmental progression were both dependent on plasma membrane association of Igα/Igβ complexes and intact immunoregulatory tyrosine activation motifs (ITAM), thereby establishing a correlation between these processes. We believe that these studies are the first to directly demonstrate biologically relevant basal signaling through the BCR where the ability to interact with both conventional as well as nonconventional extracellular ligands is eliminated.

scholarly journals A Dual Role for Src Homology 2 Domain–Containing Inositol-5-Phosphatase (Ship) in Immunity

2000 ◽  
Vol 191 (5) ◽  
pp. 781-794 ◽  
Author(s):  
Cheryl D. Helgason ◽  
Christian P. Kalberer ◽  
Jacqueline E. Damen ◽  
Suzanne M. Chappel ◽  
Nicolas Pineault ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Lymphoid Development ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain ◽  
B Lymphoid

In this report, we demonstrate that the Src homology 2 domain–containing inositol-5-phosphatase (SHIP) plays a critical role in regulating both B cell development and responsiveness to antigen stimulation. SHIP−/− mice exhibit a transplantable alteration in B lymphoid development that results in reduced numbers of precursor B (fraction C) and immature B cells in the bone marrow. In vitro, purified SHIP−/− B cells exhibit enhanced proliferation in response to B cell receptor stimulation in both the presence and absence of Fcγ receptor IIB coligation. This enhancement is associated with increased phosphorylation of both mitogen-activated protein kinase and Akt, as well as with increased survival and cell cycling. SHIP−/− mice manifest elevated serum immunoglobulin (Ig) levels and an exaggerated IgG response to the T cell–independent type 2 antigen trinitrophenyl Ficoll. However, only altered B cell development was apparent upon transplantation into nonobese diabetic–severe combined immunodeficient (NOD/SCID) mice. The in vitro hyperresponsiveness, together with the in vivo findings, suggests that SHIP regulates B lymphoid development and antigen responsiveness by both intrinsic and extrinsic mechanisms.

RNAi Screening Identifies A Novel Role for A-Kinase Anchoring Protein 12 (AKAP12) in B Cell Development and Function

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 855-855 ◽  
Author(s):  
Mutlu Kartal-Kaess ◽  
Luisa Cimmino ◽  
Simona Infantino ◽  
Mehmet Yabas ◽  
Jian-Guo Zhang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Leukemia Cell ◽  
Cell Development ◽  
B Cell Development ◽  
Leukemia Cell Line ◽  
B Lymphopoiesis ◽  
Catalytic Subunits ◽  
B Cell Leukemia

Abstract Abstract 855 The cAMP signaling pathway has emerged as a key regulator of hematopoietic cell proliferation, differentiation, and apoptosis. Signal specificity is achieved through local activation of signaling enzymes that are anchored to subcellular organelles and membranes. In particular, A-kinase anchoring proteins (AKAPs) coordinate and control cAMP responsive events. AKAPs were originally classified based on their ability to bind cAMP-dependent protein kinase (protein kinase A; PKA). The activity of PKA is regulated by its two regulatory subunits, which from a dimer that binds to the two catalytic subunits. Binding of cAMP to the regulatory dimer dissociates the catalytic subunits and activates PKA. Anchoring of PKA by AKAPs constrains PKA activity to a relevant subset of potential substrates. Thus, AKAPs contribute to the precision of intracellular signaling events by directing anchored enzyme pools to a subset of their physiological substrates at specific subcellular localizations. Using an in vitro short hairpin RNA (shRNA) screen against potentially druggable targets, we have uncovered a requirement for AKAP12 in the proliferation of a cultured pre-B cell leukemia cell line. In the hematopoietic system of mice and humans, expression of AKAP12 is tightly restricted to the pro/pre/immature stages of B lymphopoiesis, suggesting a potential role in pre-B cell receptor (pre-BCR) or BCR signaling. We find that retroviral knockdown or germline knockout of AKAP12 in mice leads to an increase in pre B and immature B cells in the bone marrow. In contrast, B cell numbers in the spleen are significantly reduced, as are recirculating B cells in the bone marrow. Transplantation of AKAP12 null hematopoietic stem and progenitor cells from fetal liver into wildtype recipients demonstrates an autonomous defect in the development of AKAP12−/− B cells. Competitive bone marrow transplantations confirm that this defect is cell autonomous and not due to a defective bone marrow environment or secretion of a B cell inhibitory factor. To identify AKAP12 interaction partners, we overexpressed FLAG-epitope tagged AKAP12 in a pre-B cell leukemia cell line. Affinity purification of AKAP12 showed a repeated co-immunoprecipitation of poorly characterized RIO kinase 1 (RIOK1). Our current efforts are focused on investigating the interaction between RIOK1 and AKAP12 and their role in the control of B cell development and cell cycle progression. Further, we are focusing on a likely role for AKAP12 in the scaffolding of PKA, PKC and phosphodiesterases by analyzing the activation of signaling cascades in cultured primary wildtype and AKAP12−/− pre B cells. Additionally, we are investigating the role of the BCR in vivo by testing if enforced expression of BCR components rescue B cell development in a AKAP12−/− BCR transgenic mouse model (SWHEL mouse). In summary, we have confirmed a novel role for AKAP12 in B lymphopoiesis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals IRF-4 functions as a tumor suppressor in early B-cell development

Blood ◽  
2008 ◽  
Vol 112 (9) ◽  
pp. 3798-3806 ◽  
Author(s):  
Jaime Acquaviva ◽  
Xiaoren Chen ◽  
Ruibao Ren
Keyword(s):  
Tumor Suppressor ◽  
B Cell ◽  
Kinase Inhibitor ◽  
Lymphoblastic Leukemia ◽  
Cell Development ◽  
B Cell Development ◽  
Lymphoid Progenitors ◽  
B Lymphoid

Interferon regulatory factor-4 (IRF-4) is a hematopoietic cell–restricted transcription factor important for hematopoietic development and immune response regulation. It was also originally identified as the product of a proto-oncogene involved in chromosomal translocations in multiple myeloma. In contrast to its oncogenic function in late stages of B lymphopoiesis, expression of IRF-4 is down-regulated in certain myeloid and early B-lymphoid malignancies. In this study, we found that the IRF-4 protein levels are increased in lymphoblastic cells transformed by the BCR/ABL oncogene in response to BCR/ABL tyrosine kinase inhibitor imatinib. We further found that IRF-4 deficiency enhances BCR/ABL transformation of B-lymphoid progenitors in vitro and accelerates disease progression of BCR/ABL-induced acute B-lymphoblastic leukemia (B-ALL) in mice, whereas forced expression of IRF-4 potently suppresses BCR/ABL transformation of B-lymphoid progenitors in vitro and BCR/ABL-induced B-ALL in vivo. Further analysis showed that IRF-4 inhibits growth of BCR/ABL+ B lymphoblasts primarily through negative regulation of cell-cycle progression. These results demonstrate that IRF-4 functions as tumor suppressor in early B-cell development and may allow elucidation of new molecular pathways significant to the lymphoid leukemogenesis by BCR/ABL. The context dependent roles of IRF-4 in oncogenesis should be an important consideration in developing cancer therapies targeting IRF-4.

scholarly journals Long noncoding RNAs in B-cell development and activation

Blood ◽  
2016 ◽  
Vol 128 (7) ◽  
pp. e10-e19 ◽  
Author(s):  
Tiago F. Brazão ◽  
Jethro S. Johnson ◽  
Jennifer Müller ◽  
Andreas Heger ◽  
Chris P. Ponting ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
De Novo ◽  
Lymphoblastic Leukemia ◽  
Cell Lineage ◽  
Noncoding Rnas ◽  
Cell Development ◽  
B Cell Development ◽  
Long Noncoding Rnas ◽  
Human B Cells

AbstractLong noncoding RNAs (lncRNAs) are potentially important regulators of cell differentiation and development, but little is known about their roles in B lymphocytes. Using RNA-seq and de novo transcript assembly, we identified 4516 lncRNAs expressed in 11 stages of B-cell development and activation. Most of these lncRNAs have not been previously detected, even in the closely related T-cell lineage. Comparison with lncRNAs previously described in human B cells identified 185 mouse lncRNAs that have human orthologs. Using chromatin immunoprecipitation-seq, we classified 20% of the lncRNAs as either enhancer-associated (eRNA) or promoter-associated RNAs. We identified 126 eRNAs whose expression closely correlated with the nearest coding gene, thereby indicating the likely location of numerous enhancers active in the B-cell lineage. Furthermore, using this catalog of newly discovered lncRNAs, we show that PAX5, a transcription factor required to specify the B-cell lineage, bound to and regulated the expression of 109 lncRNAs in pro-B and mature B cells and 184 lncRNAs in acute lymphoblastic leukemia.

scholarly journals Key pathways are frequently mutated in high-risk childhood acute lymphoblastic leukemia: a report from the Children's Oncology Group

Blood ◽  
2011 ◽  
Vol 118 (11) ◽  
pp. 3080-3087 ◽  
Author(s):  
Jinghui Zhang ◽  
Charles G. Mullighan ◽  
Richard C. Harvey ◽  
Gang Wu ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Lymphoblastic Leukemia ◽  
High Risk ◽  
B Cell ◽  
High Frequency ◽  
Lymphoblastic Leukemia ◽  
Cell Development ◽  
B Cell Development ◽  
Ras Signaling ◽  
Somatic Alterations

Abstract We sequenced 120 candidate genes in 187 high-risk childhood B-precursor acute lymphoblastic leukemias, the largest pediatric cancer genome sequencing effort reported to date. Integrated analysis of 179 validated somatic sequence mutations with genome-wide copy number alterations and gene expression profiles revealed a high frequency of recurrent somatic alterations in key signaling pathways, including B-cell development/differentiation (68% of cases), the TP53/RB tumor suppressor pathway (54%), Ras signaling (50%), and Janus kinases (11%). Recurrent mutations were also found in ETV6 (6 cases), TBL1XR1 (3), CREBBP (3), MUC4 (2), ASMTL (2), and ADARB2 (2). The frequency of mutations within the 4 major pathways varied markedly across genetic subtypes. Among 23 leukemias expressing a BCR-ABL1-like gene expression profile, 96% had somatic alterations in B-cell development/differentiation, 57% in JAK, and 52% in both pathways, whereas only 9% had Ras pathway mutations. In contrast, 21 cases defined by a distinct gene expression profile coupled with focal ERG deletion rarely had B-cell development/differentiation or JAK kinase alterations but had a high frequency (62%) of Ras signaling pathway mutations. These data extend the range of genes that are recurrently mutated in high-risk childhood B-precursor acute lymphoblastic leukemia and highlight important new therapeutic targets for selected patient subsets.

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