Publications by authors named "Emmanuelle Clappier"

45 Publications

Determinants of CD19-positive vs CD19-negative relapse after tisagenlecleucel for B-cell acute lymphoblastic leukemia.

Leukemia 2021 May 17. Epub 2021 May 17.

Department of Pediatric Hematology and Immunology, AP-HP, Hôpital Universitaire Robert Debré, Paris, France.

Tisagenlecleucel therapy has shown promising efficacy for relapsed/refractory (R/R) B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, relapses occur in 30-50% of patients. Determinants for CD19 versus CD19 relapses are poorly characterized. We report on 51 patients with R/R BCP-ALL (median age 17 years) infused with tisagenlecleucel after lymphodepletion. Complete remission rate at D28 was 96%. Prior blinatumomab increased the risk of early failure at D28. The 18-month cumulative incidence of relapse (CIR), event-free survival (EFS), and overall survival (OS) were 51%, 44%, and 74%, respectively, at a median follow-up of 15.5 months. Factors associated with a high tumor burden (occurrence of cytokine release syndrome) and prior blinatumomab were associated with an increased CIR, and a shorter EFS and OS. Pre-lymphodepletion high disease burden (MRD ≥ 10, SHR 10.4, p = 0.03) and detectable MRD at D28 (SHR 7.2, p = 0.006) correlated with an increased risk of CD19 relapse. Low disease burden (SHR 5.3, p = 0.03) and loss of B-cell aplasia (BCA) (SHR 21.7, p = 0.004) predicted an increased risk of CD19 relapses. These data highlight the impact of prior therapy on patient outcome. Finally, detectable MRD at D28 and loss of BCA both define patients at high risk of relapse for whom additional interventions are needed.
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http://dx.doi.org/10.1038/s41375-021-01281-7DOI Listing
May 2021

Multicenter Next-Generation Sequencing Studies between Theory and Practice: Harmonization of Data Analysis Using Real-World Myelodysplastic Syndrome Data.

J Mol Diagn 2021 03 23;23(3):347-357. Epub 2020 Dec 23.

Institute of Medical Informatics, University of Münster, Münster, Germany.

In the age of personalized medicine, genetic testing by means of targeted sequencing has taken a key role. However, when comparing different sets of targeted sequencing data, these are often characterized by a considerable lack of harmonization. Laboratories follow their own best practices, analyzing their own target regions. The question on how to best integrate data from different sites remains unanswered. Studying the example of myelodysplastic syndrome (MDS), we analyzed 11 targeted sequencing sets, collected from six different centers (n = 831). An intersecting target region of 43,076 bp (30 genes) was identified; whereas, the original target regions covered up to 499,097 bp (117 genes). Considering a region of interest in the context of MDS, a target region of 55,969 bp (31 genes) was identified. For each gene, coverage and sequencing data quality was evaluated, calculating a sequencing score. Analyses revealed huge differences between different data sets as well as between different genes. Analysis of the relation between sequencing score and mutation frequency in MDS revealed that most genes with high frequency in MDS could be sequenced without expecting low coverage or quality. Still, no gene appeared consistently unproblematic for all data sets. To allow for comparable results in a multicenter setting analyzing MDS, we propose to use a predefined target region of interest and to perform centralized data analysis using harmonized criteria.
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http://dx.doi.org/10.1016/j.jmoldx.2020.12.001DOI Listing
March 2021

T-Cell Acute Lymphoblastic Leukemia in a Young Adult With Thrombocytopenia-absent Radius Syndrome: A Case Report and Review of the Literature.

J Pediatr Hematol Oncol 2020 Aug 18. Epub 2020 Aug 18.

Hematology Adolescent and Young Adults Unit, Saint-Louis Hospital, Assistance Publique-Hôpitaux de Paris.

Thrombocytopenia-absent radius (TAR) syndrome is a rare inherited bone marrow failure syndrome not generally associated with acute leukemia. The authors report a case of T-cell acute lymphoblastic leukemia in an adult female individual newly diagnosed with TAR syndrome. A 347-kb microdeletion of chromosome 1q21.1 involving the RBM8A gene was detected within a gain of whole chromosome 1. Next-generation sequencing on fibroblasts confirmed germline heterozygous deletion of RBM8A but on the other allele, noncoding low-frequency regulatory single-nucleotide polymorphism of RBM8A (rs139428292; rs201779890) were not found. The tolerance of the treatment was unusual and mostly marked by a slow hematopoietic recovery leading to a 6-month delay at the beginning of the maintenance phase. Only 5 cases of acute leukemia were reported in patients with TAR syndrome in the literature: 4 acute myeloid leukemia and one B-cell acute lymphoblastic leukemia. This is the first report of T-cell acute lymphoid leukemia occurring in the context of TAR syndrome.
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http://dx.doi.org/10.1097/MPH.0000000000001919DOI Listing
August 2020

Clonal dominance is an adverse prognostic factor in acute myeloid leukemia treated with intensive chemotherapy.

Leukemia 2021 03 24;35(3):712-723. Epub 2020 Jun 24.

Service Hématologie Adultes, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, F-75010, Paris, France.

Intra-tumor heterogeneity portends poor outcome in many cancers. In AML, a higher number of drivers worsens prognosis. The Shannon Index is a robust metric of clonal heterogeneity that accounts for the number of clones, but also their relative abundance. We show that a Shannon Index can be estimated from bulk sequencing, which is correlated (ρ = 0.76) with clonal diversity from single-colony genotyping. In a discovery cohort of 292 patients with sequencing of 43 genes, a higher number of drivers (HR = 1.18, P = 0.028) and a lower Shannon Index (HR = 0.68, P = 0.048), the latter reflecting clonal dominance, are independently associated with worse OS independently of European LeukemiaNet 2017 risk. These findings are validated in an independent cohort of 1184 patients with 111-gene sequencing (number of drivers HR = 1.16, P = 1 × 10, Shannon Index HR = 0.81, P = 0.007). By re-interrogating paired diagnosis/relapse exomes from 50 cytogenetically normal AMLs, we find clonal dominance at diagnosis to be correlated with the gain of a significantly higher number of mutations at relapse (P = 6 × 10), hence with clonal sweeping. Our results suggest that clonal dominance at diagnosis is associated with the presence of a leukemic phenotype allowing rapid expansion of new clones and driving relapse after chemotherapy.
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http://dx.doi.org/10.1038/s41375-020-0932-8DOI Listing
March 2021

Should Transplantation Still Be Considered for Ph1-Negative Myeloproliferative Neoplasms in Transformation?

Biol Blood Marrow Transplant 2020 06 28;26(6):1160-1170. Epub 2020 Feb 28.

Hematology and Transplantation, Saint Louis Hospital, Paris, France; University of Paris, INSERM U976, Paris, France. Electronic address:

BCR-ABL-negative myeloproliferative neoplasms (MPNs) in transformation have a dismal prognosis, and allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered the sole curative therapeutic option. We retrospectively analyzed 53 molecularly annotated patients treated at Saint Louis Hospital, Paris, diagnosed with MPN in transformation between 2008 and 2018. The median patient age was 65 years, and the median interval between MPN diagnosis and MPN transformation was 46 months. The median overall survival (OS) of the entire cohort after transformation was 7.1 months. OS was better for patients treated with hypomethylating agents (HMAs) or with chemotherapy compared than for those treated by best supportive care or single-agent targeted therapy (median, 9.1 months versus 1.5 months; P < .001). Patients treated with chemotherapy more often achieved complete remission compared with those treated with HMAs (68% versus 29%; P = .02), and were more often candidates for transplantation (59% versus 14%; P = .02), but the median OS was similar in the 2 groups. We then compared the outcomes in transplant recipients and nonrecipients using the Mantel-Byar methodology and found that allo-HSCT did not improve survival. In multivariate analysis, independent factors in prognosis were performance status at transformation (P < .01), initial treatment with HMAs or chemotherapy (P = .02), and the ability to achieve complete remission during follow-up (P < .01). Our data demonstrate that the indication for allo-HSCT for high-risk MPN should be discussed before transformation, because transplantation rescues few patients after transformation.
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http://dx.doi.org/10.1016/j.bbmt.2020.02.019DOI Listing
June 2020

Next-Generation Sequencing in Myeloid Neoplasm-Associated Sweet's Syndrome Demonstrates Clonal Relation between Malignant Cells and Skin-Infiltrating Neutrophils.

J Invest Dermatol 2020 09 17;140(9):1873-1876.e5. Epub 2020 Feb 17.

Université de Paris, Paris, France; INSERM UMR976, Centre de Recherche sur la Peau, Paris, France; Dermatology Department, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Paris, France. Electronic address:

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http://dx.doi.org/10.1016/j.jid.2019.12.040DOI Listing
September 2020

B-ALL With t(5;14)(q31;q32); Rearrangement and Eosinophilia: A Comprehensive Analysis of a Peculiar -Rearranged B-ALL.

Front Oncol 2019 10;9:1374. Epub 2019 Dec 10.

Department of Pediatric Hematology and Immunology, University Hospital Robert Debré, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France.

B-cell acute lymphoblastic leukemia associated with t(5;14)(q31;q32); is an exceptional cause of eosinophilia. The enhancer on 14q32 is juxtaposed to the gene on 5q31, leading to interleukin-3 overproduction and release of mature eosinophils in the blood. Clinical, biological and outcome data are extremely scarce in the literature. Except for eosinophilia, no relevant common feature has been highlighted in these patients. However, it has been classified as a distinct entity in the World Health Organization classification. Eight patients with t(5;14)(q31;q32) treated by French or Austrian protocols were retrospectively enrolled. Array comparative genomic hybridization, multiplex ligation-dependent probe amplification or genomic PCR search for deletion were performed in 7. Sixteen patients found through an exhaustive search in the literature were also analyzed. For those 24 patients, median age at diagnosis is 14.3 years with a male predominance (male to female ratio = 5). Eosinophilia-related symptoms are common (neurologic in 26%, thromboembolic in 26% or pulmonary in 50%). Median white blood cells count is high (72 × 10/L) and linked to eosinophilia (median: 32 × 10/L). Peripheral blasts are present at a low level or absent (median: 0 × 10/L; range: 0-37 × 10/L). Bone marrow morphology is marked by a low blast infiltration (median: 42%). We found an deletion in 5 out of 7 analyzable patients Outcome data are available for 14 patients (median follow-up: 28 months): 8 died and 6 are alive in complete remission. Some of these features are concordant with those seen in patients with other -rearranged B-cell acute lymphoblastic leukemias: young age at onset, male sex, low blast count, high incidence of deletion and intermediate prognosis. Based on shared epidemiological and biological features, B-cell acute lymphoblastic leukemia with t(5;14)(q31;q32) is a peculiar subset of -rearranged B-cell acute lymphoblastic leukemia with an intermediate prognosis and particular clinical features related to eosinophilia.
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http://dx.doi.org/10.3389/fonc.2019.01374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914849PMC
December 2019

Genetic landscape of adult Langerhans cell histiocytosis with lung involvement.

Eur Respir J 2020 02 27;55(2). Epub 2020 Feb 27.

Université de Paris, INSERM U976, Institut de Recherche Saint-Louis, Paris, France

The clinical significance of the mutation in adult Langerhans cell histiocytosis (LCH), including pulmonary Langerhans cell histiocytosis (PLCH), is not well understood. Similarly, the spectrum of molecular alterations involved in adult LCH has not been fully delineated. To address these issues, we genotyped a large number of adult LCH biopsies and searched for an association of identified molecular alterations with clinical presentation and disease outcome.Biopsies from 117 adult LCH patients, 83 with PLCH (median age 36.4 years, 56 females, 38 multisystem disease, 79 single system disease, 65 current smokers) were genotyped for the mutation. In 69 cases, LCH lesions were also genotyped by whole-exome sequencing (WES) or targeted gene panel next-generation sequencing (NGS). Cox models were used to estimate the association of baseline characteristics with the hazard of LCH progression.MAPK pathway alterations were detected in 59 out of 69 cases (86%) ( mutation: 36%, deletion: 28%, mutations: 15%, isolated mutations: 4%), while mutations were virtually absent in PLCH lesions. The mutation was not associated with LCH presentation at diagnosis, including smoking status and lung function, in PLCH patients. status did not influence the risk of LCH progression over time.Thus, MAPK alterations are present in most lesions from adult LCH patients, particularly in PLCH. Unlike reports in paediatric LCH, genotyping did not provide additional information on disease outcome. The search for alterations involved in the MAPK pathway, including deletions, is useful for guiding targeted treatment in selected patients with refractory progressive LCH.
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http://dx.doi.org/10.1183/13993003.01190-2019DOI Listing
February 2020

BET inhibitors impair leukemic stem cell function only in defined oncogenic subgroups of acute myeloid leukaemias.

Leuk Res 2019 12 7;87:106269. Epub 2019 Nov 7.

INSERM/CNRS UMR 944/7212, Paris, France; Institut Universitaire d'Hématologie, Université Paris Diderot, Sorbonne Paris Cité, Paris Cancer Research Institute (PACRI), Paris, France; Département d'Hématologie, Hôpital Saint-Louis, Assistance Publique - Hopitaux de Paris, France. Electronic address:

Bromodomain and Extra-Terminal inhibitors (BETi) such as OTX015 are active in Acute Myeloid Leukaemias (AML). Their activity on Leukemic Stem Cells (LSCs) is less documented. We interrogated the anti-LSC activity of OTX015 in a niche-like long-term culture in 26 primary AML samples and validated our findings in vivo. OTX015 impaired LSCs in AMLs harbouring Core Binding Factor or KMT2A gene fusions, NPM1 or chromatin/spliceosome genes mutations, but not in those with aneuploidy/TP53 mutations. In four patients, we dissected the transcriptomic footprint of Bet inhibition on LSCs versus blasts. Our results can instruct future clinical trials of BETi in AML.
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http://dx.doi.org/10.1016/j.leukres.2019.106269DOI Listing
December 2019

Germline DDX41 mutations define a significant entity within adult MDS/AML patients.

Blood 2019 10;134(17):1441-1444

Institut de Recherche Saint-Louis, INSERM U944/CNRS Unité Mixte de Recherche (UMR) 7212, Paris, France.

Germline DDX41 mutations are involved in familial myelodysplastic syndromes (MDSs) and acute myeloid leukemias (AMLs). We analyzed the prevalence and characteristics of DDX41-related myeloid malignancies in an unselected cohort of 1385 patients with MDS or AML. Using targeted next-generation sequencing, we identified 28 different germline DDX41 variants in 43 unrelated patients, which we classified as causal (n = 21) or unknown significance (n = 7) variants. We focused on the 33 patients having causal variants, representing 2.4% of our cohort. The median age was 69 years; most patients were men (79%). Only 9 patients (27%) had a family history of hematological malignancy, and 15 (46%) had a personal history of cytopenia years before MDS/AML diagnosis. Most patients had a normal karyotype (85%), and the most frequent somatic alteration was a second DDX41 mutation (79%). High-risk DDX41 MDS/AML patients treated with intensive chemotherapy (n = 9) or azacitidine (n = 11) had an overall response rate of 100% or 73%, respectively, with a median overall survival of 5.2 years. Our study highlights that germline DDX41 mutations are relatively common in adult MDS/AML, often without known family history, arguing for systematic screening. Salient features of DDX41-related myeloid malignancies include male preponderance, frequent preexisting cytopenia, additional somatic DDX41 mutation, and relatively good outcome.
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http://dx.doi.org/10.1182/blood.2019000909DOI Listing
October 2019

Role of Donor Clonal Hematopoiesis in Allogeneic Hematopoietic Stem-Cell Transplantation.

J Clin Oncol 2019 02 7;37(5):375-385. Epub 2018 Nov 7.

5 University Hospital Ulm, Ulm, Germany.

Purpose: Clonal hematopoiesis of indeterminate potential (CHIP) occurs in the blood of approximately 20% of older persons. CHIP is linked to an increased risk of hematologic malignancies and of all-cause mortality; thus, the eligibility of stem-cell donors with CHIP is questionable. We comprehensively investigated how donor CHIP affects outcome of allogeneic hematopoietic stem-cell transplantation (HSCT).

Methods: We collected blood samples from 500 healthy, related HSCT donors (age ≥ 55 years) at the time of stem-cell donation for targeted sequencing with a 66-gene panel. The effect of donor CHIP was assessed on recipient outcomes, including graft-versus-host disease (GVHD), cumulative incidence of relapse/progression (CIR/P), and overall survival (OS).

Results: A total of 92 clonal mutations with a median variant allele frequency of 5.9% were identified in 80 (16.0%) of 500 donors. CHIP prevalence was higher in donors related to patients with myeloid compared with lymphoid malignancies (19.2% v 6.3%; P ≤ .001). In recipients allografted with donor CHIP, we found a high cumulative incidence of chronic GVHD (cGVHD; hazard ratio [HR], 1.73; 95% CI, 1.21 to 2.49; P = .003) and lower CIR/P (univariate: HR, 0.62; 95% CI, 0.40 to 0.97; P = .027; multivariate: HR, 0.63; 95% CI, 0.41 to 0.98; P = .042) but no effect on nonrelapse mortality. Serial quantification of 25 mutations showed engraftment of 24 of 25 clones and disproportionate expansion in half of them. Donor-cell leukemia was observed in two recipients. OS was not affected by donor CHIP status (HR, 0.88; 95% CI, 0.65 to 1.321; P = .434).

Conclusion: Allogeneic HSCT from donors with CHIP seems safe and results in similar survival in the setting of older, related donors. Future studies in younger and unrelated donors are warranted to extend these results. Confirmatory studies and mechanistic experiments are warranted to challenge the hypothesis that donor CHIP might foster cGVHD development and reduce relapse/progression risk.
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http://dx.doi.org/10.1200/JCO.2018.79.2184DOI Listing
February 2019

Deletion 6q Drives T-cell Leukemia Progression by Ribosome Modulation.

Cancer Discov 2018 12 28;8(12):1614-1631. Epub 2018 Sep 28.

INSERM UMR944 and CNRS UMR7212, Hôpital Saint-Louis, Paris, France.

Deletion of chromosome 6q is a well-recognized abnormality found in poor-prognosis T-cell acute lymphoblastic leukemia (T-ALL). Using integrated genomic approaches, we identified two candidate haploinsufficient genes contiguous at 6q14, (encoding hnRNP-Q) and (that hosts snoRNAs), both involved in regulating RNA maturation and translation. Combined silencing of both genes, but not of either gene alone, accelerated leukemogeneis in a -driven mouse model, demonstrating the tumor-suppressive nature of the two-gene region. Proteomic and translational profiling of cells in which we engineered a short 6q deletion by CRISPR/Cas9 genome editing indicated decreased ribosome and mitochondrial activities, suggesting that the resulting metabolic changes may regulate tumor progression. Indeed, xenograft experiments showed an increased leukemia-initiating cell activity of primary human leukemic cells upon coextinction of and Our findings not only elucidate the nature of 6q deletion but also highlight the role of ribosomes and mitochondria in T-ALL tumor progression. SIGNIFICANCE: The oncogenic role of 6q deletion in T-ALL has remained elusive since this chromosomal abnormality was first identified more than 40 years ago. We combined genomic analysis and functional models to show that the codeletion of two contiguous genes at 6q14 enhances malignancy through deregulation of a ribosome-mitochondria axis, suggesting the potential for therapeutic intervention..
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http://dx.doi.org/10.1158/2159-8290.CD-17-0831DOI Listing
December 2018

Myelodysplastic syndrome (MDS) with isolated trisomy 8: a type of MDS frequently associated with myeloproliferative features? A report by the Groupe Francophone des Myélodysplasies.

Br J Haematol 2018 09 13;182(6):843-850. Epub 2018 Jul 13.

Hôpital Saint-Louis, Assistance Publique Hôpitaux de Paris (APHP), University Paris Diderot (Paris 7), Paris, France.

Isolated trisomy 8 (+8) is a frequent cytogenetic abnormality in the myelodysplastic syndromes (MDS), but its characteristics are poorly reported. We performed a retrospective study of 138 MDS patients with isolated +8, classified or reclassified as MDS (excluding MDS/myeloproliferative neoplasm). Myeloproliferative (MP) features were defined by the repeated presence of one of the following: white blood cell count >10 × 10 /l, myelemia (presence of circulating immature granulocytes with a predominance of more mature forms) >2%, palpable splenomegaly. Fifty-four patients (39·1%) had MP features: 28 at diagnosis, 26 were acquired during evolution. MP forms had more EZH2 (33·3% vs. 12·0% in non-MP, P = 0·047), ASXL1 (66·7% vs. 42·3%, P = 0·048) and STAG2 mutations (77·8% vs. 21·7%, P = 0·006). Median event-free survival (EFS) and overall survival (OS) were 25 and 27 months for patients with MP features at diagnosis, versus 28 (P = 0·15) and 39 months (P = 0·085) for those without MP features, respectively. Among the 57 patients who received hypomethylating agent (HMA), OS was lower in MP cases (13 months vs. 23 months in non-MP cases, P = 0.02). In conclusion, MP features are frequent in MDS with isolated +8. MP forms had more EZH2, ASXL1 and STAG2 mutations, responded poorly to HMA, and tended to have poorer survival than non-MP forms.
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http://dx.doi.org/10.1111/bjh.15490DOI Listing
September 2018

Aggressive B-cell lymphomas in patients with myelofibrosis receiving JAK1/2 inhibitor therapy.

Blood 2018 08 14;132(7):694-706. Epub 2018 Jun 14.

Division of Hematology and Hemostaseology, Department of Internal Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.

Inhibition of Janus-kinase 1/2 (JAK1/2) is a mainstay to treat myeloproliferative neoplasms (MPN). Sporadic observations reported the co-incidence of B-cell non-Hodgkin lymphomas during treatment of MPN with JAK1/2 inhibitors. We assessed 626 patients with MPN, including 69 with myelofibrosis receiving JAK1/2 inhibitors for lymphoma development. B-cell lymphomas evolved in 4 (5.8%) of 69 patients receiving JAK1/2 inhibition compared with 2 (0.36%) of 557 with conventional treatment (16-fold increased risk). A similar 15-fold increase was observed in an independent cohort of 929 patients with MPN. Considering primary myelofibrosis only (N = 216), 3 lymphomas were observed in 31 inhibitor-treated patients (9.7%) vs 1 (0.54%) of 185 control patients. Lymphomas were of aggressive B-cell type, extranodal, or leukemic with high MYC expression in the absence of V617F or other MPN-associated mutations. Median time from initiation of inhibitor therapy to lymphoma diagnosis was 25 months. Clonal immunoglobulin gene rearrangements were already detected in the bone marrow during myelofibrosis in 16.3% of patients. Lymphomas occurring during JAK1/2 inhibitor treatment were preceded by a preexisting B-cell clone in all 3 patients tested. Sequencing verified clonal identity in 2 patients. The effects of JAK1/2 inhibition were mirrored in mice: 16 of 24 mice developed a spontaneous myeloid hyperplasia with the concomitant presence of aberrant B cells. Transplantations of bone marrow from diseased mice unmasked the outgrowth of a malignant B-cell clone evolving into aggressive B-cell leukemia-lymphoma. We conclude that JAK/STAT1 pathway inhibition in myelofibrosis is associated with an elevated frequency of aggressive B-cell lymphomas. Detection of a preexisting B-cell clone may identify individuals at risk.
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http://dx.doi.org/10.1182/blood-2017-10-810739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115916PMC
August 2018

A landscape of germ line mutations in a cohort of inherited bone marrow failure patients.

Blood 2018 02 16;131(7):717-732. Epub 2017 Nov 16.

Pediatric Hematology Immunology Unit, Necker-Enfants-Malades Hospital, Paris, France.

Bone marrow (BM) failure (BMF) in children and young adults is often suspected to be inherited, but in many cases diagnosis remains uncertain. We studied a cohort of 179 patients (from 173 families) with BMF of suspected inherited origin but unresolved diagnosis after medical evaluation and Fanconi anemia exclusion. All patients had cytopenias, and 12.0% presented ≥5% BM blast cells. Median age at genetic evaluation was 11 years; 20.7% of patients were aged ≤2 years and 36.9% were ≥18 years. We analyzed genomic DNA from skin fibroblasts using whole-exome sequencing, and were able to assign a causal or likely causal germ line mutation in 86 patients (48.0%), involving a total of 28 genes. These included genes in familial hematopoietic disorders (, ), telomeropathies (, , ), ribosome disorders (, , ), and DNA repair deficiency (). Many patients had an atypical presentation, and the mutated gene was often not clinically suspected. We also found mutations in genes seldom reported in inherited BMF (IBMF), such as and (N = 16 of the 86 patients, 18.6%), (N = 6, 7.0%), and (N = 7, 8.1%), each of which was associated with a distinct natural history; and patients often experienced transient aplasia and monosomy 7, whereas patients presented early-onset severe aplastic anemia, and patients, mild pancytopenia with myelodysplasia. This study broadens the molecular and clinical portrait of IBMF syndromes and sheds light on newly recognized disease entities. Using a high-throughput sequencing screen to implement precision medicine at diagnosis can improve patient management and family counseling.
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http://dx.doi.org/10.1182/blood-2017-09-806489DOI Listing
February 2018

Speed of leukemia development and genetic diversity in xenograft models of T cell acute lymphoblastic leukemia.

Oncotarget 2016 Jul;7(27):41599-41611

Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), DSV-IRCM-SCSR-LSHL, UMR 967, Fontenay-aux-Roses, France.

T cell acute lymphoblastic leukemia (T-ALL) develops through accumulation of multiple genomic alterations within T-cell progenitors resulting in clonal heterogeneity among leukemic cells. Human T-ALL xeno-transplantation in immunodeficient mice is a gold standard approach to study leukemia biology and we recently uncovered that the leukemia development is more or less rapid depending on T-ALL sample. The resulting human leukemia may arise through genetic selection and we previously showed that human T-ALL development in immune-deficient mice is significantly enhanced upon CD7+/CD34+ leukemic cell transplantations. Here we investigated the genetic characteristics of CD7+/CD34+ and CD7+/CD34- cells from newly diagnosed human T-ALL and correlated it to the speed of leukemia development. We observed that CD7+/CD34+ or CD7+/CD34- T-ALL cells that promote leukemia within a short-time period are genetically similar, as well as xenograft-derived leukemia resulting from both cell fractions. In the case of delayed T-ALL growth CD7+/CD34+ or CD7+/CD34- cells were either genetically diverse, the resulting xenograft leukemia arising from different but branched subclones present in the original sample, or similar, indicating decreased fitness to mouse micro-environment. Altogether, our work provides new information relating the speed of leukemia development in xenografts to the genetic diversity of T-ALL cell compartments.
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http://dx.doi.org/10.18632/oncotarget.9313DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5173081PMC
July 2016

Different outcome of T cell acute lymphoblastic leukemia with translocation t(11;14) treated in two consecutive children leukemia group EORTC trials.

Ann Hematol 2016 Jan 12;95(1):93-103. Epub 2015 Oct 12.

Department of Pediatric Hematology-Oncology, CHU, Besançon, France.

Acute lymphoblastic leukemia of T cell lineage (T-ALL) is an aggressive malignant disease which accounts for 15 % of childhood ALL. T(11;14) is the more frequent chromosomal abnormality in childhood T-ALL, but its prognostic value remained controversial. Our aim was to analyze the outcome of childhood T-ALL with t(11;14) to know if the presence of this translocation is associated with a poor prognosis. We conducted a retrospective study from a series of 20 patients with t(11;14), treated in two consecutive trials from the European Organization for Research and Treatment of Cancer Children Leukemia Group over a 19-year period from 1989 to 2008. There were no significant differences between the 2 consecutive groups of patients with t(11;14) regarding the clinical and biological features at diagnosis. Among 19 patients who reached complete remission, 9 patients relapsed. We noticed 7 deaths all relapse- or failure-related. In the 58881 study, a presence of t(11;14) was associated with a poor outcome with an event-free survival at 5 years at 22.2 % versus 65.1 % for the non-t(11;14) T-ALL (p = 0.0004). In the more recent protocol, the outcome of T-ALL with t(11;14) reached that of non-t(11;14) T-ALL with an event-free survival at 5 years at 65.5 versus 74.9 % (p = 0.93). The presence of t(11;14) appeared as a poor prognostic feature in the 58881 trial whereas this abnormality no longer affected the outcome in the 58951 study. This difference is probably explained by the more intensive chemotherapy in the latest trial.
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http://dx.doi.org/10.1007/s00277-015-2515-8DOI Listing
January 2016

Targeted sequencing identifies associations between IL7R-JAK mutations and epigenetic modulators in T-cell acute lymphoblastic leukemia.

Haematologica 2015 Oct 23;100(10):1301-10. Epub 2015 Jul 23.

Center for Human Genetics, KU Leuven, Belgium Center for the Biology of Disease, VIB, Leuven, Belgium

T-cell acute lymphoblastic leukemia is caused by the accumulation of multiple oncogenic lesions, including chromosomal rearrangements and mutations. To determine the frequency and co-occurrence of mutations in T-cell acute lymphoblastic leukemia, we performed targeted re-sequencing of 115 genes across 155 diagnostic samples (44 adult and 111 childhood cases). NOTCH1 and CDKN2A/B were mutated/deleted in more than half of the cases, while an additional 37 genes were mutated/deleted in 4% to 20% of cases. We found that IL7R-JAK pathway genes were mutated in 27.7% of cases, with JAK3 mutations being the most frequent event in this group. Copy number variations were also detected, including deletions of CREBBP or CTCF and duplication of MYB. FLT3 mutations were rare, but a novel extracellular mutation in FLT3 was detected and confirmed to be transforming. Furthermore, we identified complex patterns of pairwise associations, including a significant association between mutations in IL7R-JAK genes and epigenetic regulators (WT1, PRC2, PHF6). Our analyses showed that IL7R-JAK genetic lesions did not confer adverse prognosis in T-cell acute lymphoblastic leukemia cases enrolled in the UK ALL2003 trial. Overall, these results identify interconnections between the T-cell acute lymphoblastic leukemia genome and disease biology, and suggest a potential clinical application for JAK inhibitors in a significant proportion of patients with T-cell acute lymphoblastic leukemia.
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http://dx.doi.org/10.3324/haematol.2015.130179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591762PMC
October 2015
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