Acute lymphoblastic leukemia (ALL) is a malignant disease of the white blood cells. The etiology ... more Acute lymphoblastic leukemia (ALL) is a malignant disease of the white blood cells. The etiology of ALL is believed to be multifactorial and likely to involve an interplay of environmental and genetic variables. We performed a genome-wide association study of 355 750 single-nucleotide polymorphisms (SNPs) in 474 controls and 419 childhood ALL cases characterized by a t(12;21)(p13;q22)-the most common chromosomal translocation observed in childhood ALL-which leads to an ETV6-RUNX1 gene fusion. The eight most strongly associated SNPs were followed-up in 951 ETV6-RUNX1-positive cases and 3061 controls from Germany/Austria and Italy, respectively. We identified a novel, genome-wide significant risk locus at 3q28 (TP63, rs17505102, P CMH ¼ 8.94 Â 10 À9 , OR ¼ 0.65). The separate analysis of the combined German/Austrian sample only, revealed additional genome-wide significant associations at 11q11 (OR8U8, rs1945213, P ¼ 9.14 Â 10 À11 , OR ¼ 0.69) and 8p21.3 (near INTS10, rs920590, P ¼ 6.12 Â 10 À9 , OR ¼ 1.36). These associations and another association at 11p11.2 (PTPRJ, rs3942852, P ¼ 4.95 Â 10 À7 , OR ¼ 0.72) remained significant in the German/Austrian replication panel after correction for multiple testing. Our findings demonstrate that germline genetic variation can specifically contribute to the risk of ETV6-RUNX1-positive childhood ALL. The identification of TP63 and PTPRJ as susceptibility genes emphasize the role of the TP53 gene family and the importance of proteins regulating cellular processes in connection with tumorigenesis.
Assessment of minimal residual disease (MRD) has acquired a prominent position in European treatm... more Assessment of minimal residual disease (MRD) has acquired a prominent position in European treatment protocols for patients with acute lymphoblastic leukemia (ALL), on the basis of its high prognostic value for predicting outcome and the possibilities for implementation of MRD diagnostics in treatment stratification. Therefore, there is an increasing need for standardization of methodologies and harmonization of terminology. For this purpose, a panel of representatives of all major European study groups on childhood and adult ALL and of international experts on PCR-and flow cytometry-based MRD assessment was built in the context of the Second International Symposium on MRD assessment in Kiel, Germany, 18-20 September 2008. The panel summarized the current state of MRD diagnostics in ALL and developed recommendations on the minimal technical requirements that should be fulfilled before implementation of MRD diagnostics into clinical trials. Finally, a common terminology for a standard description of MRD response and monitoring was established defining the terms 'complete MRD response', 'MRD persistence' and 'MRD reappearance'. The proposed MRD terminology may allow a refined and standardized assessment of response to treatment in adult and childhood ALL, and provides a sound basis for the comparison of MRD results between different treatment protocols.
Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG hi... more Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG high ICOSLG expression at diagnosis is predictive for ALL relapse EGR3 and ICOSLG expressions are relapseassociated expression of ICOSLG on t(4;11) ALL cells leads to the rapid expansion of Tregs
Juvenile myelomonocytic leukemia (JMML) treatment primarily relies on hematopoietic stem cell tra... more Juvenile myelomonocytic leukemia (JMML) treatment primarily relies on hematopoietic stem cell transplantation and results in long-term overall survival of 50-60%, demonstrating a need to develop novel treatments. Dysregulation of the non-coding RNA transcriptome has been demonstrated before in this rare and unique disorder of early childhood. In this study, we investigated the therapeutic potential of targeting overexpressed long non-coding RNAs (lncRNAs) in JMML. Total RNA sequencing of bone marrow and peripheral blood mononuclear cell preparations from 19 untreated JMML patients and three healthy children revealed 185 differentially expressed lncRNA genes (131 up-and 54 downregulated). LNA GapmeRs were designed for 10 overexpressed and validated lncRNAs. Molecular knockdown (≥ 70% compared to mock control) after 24 h of incubation was observed with two or more independent GapmeRs in 6 of them. For three lncRNAs (lnc-THADA-4, lnc-ACOT9-1 and NRIR) knockdown resulted in a significant decrease of cell viability after 72 h of incubation in primary cultures of JMML mononuclear cells, respectively. Importantly, the extent of cellular damage correlated with the expression level of the lncRNA of interest. In conclusion, we demonstrated in primary JMML cell cultures that knockdown of overexpressed lncRNAs such as lnc-THADA-4, lnc-ACOT9-1 and NRIR may be a feasible therapeutic strategy. Currently, hematopoietic stem cell transplantation (HSCT) is the established standard of care in juvenile myelomonocytic leukemia (JMML), a distinct myelodysplastic/myeloproliferative disorder of early childhood 1. HSCT results in long-term overall survival (OS) of approximately 50-60% of patients 2. Characteristic for JMML are proliferative features, such as monocytosis, splenomegaly, and a moderately elevated proportion of myeloblasts. These disease features are caused by clonal growth of an abnormal multipotent hematopoietic stem cell 3,4. In approximately 90-95% of patients, canonical mutations in the NRAS and KRAS (20-25%), PTPN11 (35%), NF1 (10-15%) or CBL (10-15%) genes are observed, strongly linking the disorder to hyperactivation of the RAS/ MAPK pathway. More recently, investigations of secondary mutations 5,6 , non-coding RNA expression 7,8 , and genomic DNA methylation 9-11 have led to a better understanding of the pathobiology of the disease. The acquisition of secondary mutations and aberrant DNA methylation were found to be associated with unfavorable clinical characteristics and poor prognosis, and might be used in the future to guide treatment decisions 5,12. Furthermore,
Juvenile myelomonocytic leukemia (JMML) is a rare aggressive myelodysplastic/myeloproliferative n... more Juvenile myelomonocytic leukemia (JMML) is a rare aggressive myelodysplastic/myeloproliferative neoplasm of early childhood, initiated by RAS-activating mutations. Genomic analyses have recently described JMML mutational landscape; however, the nature of JMML-propagating cells (JMML-PCs) and the clonal architecture of the disease remained until now elusive. Combining genomic (exome, RNA-seq), Colony forming assay and xenograft studies, we detect the presence of JMML-PCs that faithfully reproduce JMML features including the complex/nonlinear organization of dominant/minor clones, both at diagnosis and relapse. Further integrated analysis also reveals that although the mutations are acquired in hematopoietic stem cells, JMML-PCs are not always restricted to this compartment, highlighting the heterogeneity of the disease during the initiation steps. We show that the hematopoietic stem/progenitor cell phenotype is globally maintained in JMML despite overexpression of CD90/THY-1 in a subset of patients. This study shed new lights into the ontogeny of JMML, and the identity of JMML-PCs, and provides robust models to monitor the disease and test novel therapeutic approaches.
GATA2 deficiency French/Belgian cohort haematologica | 2018; 103(8) 1279 patients with nonsense o... more GATA2 deficiency French/Belgian cohort haematologica | 2018; 103(8) 1279 patients with nonsense or frameshift mutations (n=2 of 28). We also identify new features of the disease: acute lymphoblastic leukemia, juvenile myelomonocytic leukemia, fatal progressive multifocal leukoencephalopathy related to the JC virus, and immune/inflammatory diseases. A revised International Prognostic Scoring System (IPSS) score allowed a distinction to be made between a stable disease and hematologic transformation. Chemotherapy is of limited efficacy, and has a high toxicity with severe infectious complications. As the mortality rate is high in our cohort (up to 35% at the age of 40), hematopoietic stem cell transplantation (HSCT) remains the best choice of treatment to avoid severe infectious and/or hematologic complications. The timing of HSCT remains difficult to determine, but the earlier it is performed, the better the outcome.
KMT2A-rearranged acute lymphoblastic infant leukemia (KMT2A-r iALL) is associated with outsize ri... more KMT2A-rearranged acute lymphoblastic infant leukemia (KMT2A-r iALL) is associated with outsize risk of relapse and relapse mortality. We previously reported strong upregulation of the immediate early gene EGR3 in KMT2A::AFF1 iALL at relapse; now we provide analyses of the EGR3 regulome, which we assessed through binding and expression target analysis of an EGR3overexpressing t(4;11) cell culture model. Our data identify EGR3 as a regulator of early B-lineage commitment. Principal component analysis of 50 KMT2A-r iALL patients at diagnosis and 18 at relapse provided strictly dichotomous separation of patients based on the expression of four B-lineage genes. Absence of B-lineage gene expression translates to more than twofold poorer long-term event-free survival. In conclusion, our study presents four B-lineage genes with prognostic significance, suitable for gene expression-based risk stratification of KMT2A-r iALL patients.
Chromosomal rearrangements of the human KMT2A/MLL gene are associated with de novo as well as the... more Chromosomal rearrangements of the human KMT2A/MLL gene are associated with de novo as well as therapy-induced infant, pediatric, and adult acute leukemias. Here, we present the data obtained from 3401 acute leukemia patients that have been analyzed between 2003 and 2022. Genomic breakpoints within the KMT2A gene and the involved translocation partner genes (TPGs) and KMT2A-partial tandem duplications (PTDs) were determined. Including the published data from the literature, a total of 107 in-frame KMT2A gene fusions have been identified so far. Further 16 rearrangements were out-of-frame fusions, 18 patients had no partner gene fused to 5’-KMT2A, two patients had a 5’-KMT2A deletion, and one ETV6::RUNX1 patient had an KMT2A insertion at the breakpoint. The seven most frequent TPGs and PTDs account for more than 90% of all recombinations of the KMT2A, 37 occur recurrently and 63 were identified so far only once. This study provides a comprehensive analysis of the KMT2A recombinome in ...
To evaluate the prognostic significance of initial central nervous system (CNS) involvement of ch... more To evaluate the prognostic significance of initial central nervous system (CNS) involvement of children with acute lymphoblastic leukemia (ALL) enrolled in the EORTC 58951 trial. Patients and methods: From 1998 to 2008, 1930 ALL patients were included in the randomized EORTC 58951 trial. Overall treatment intensity was adjusted according to known prognostic factors including the level of minimal residual disease after induction treatment. CNS-directed therapy comprised four to 11 courses of i.v. methotrexate (5 g/m 2), and 10 to 19 intrathecal chemotherapy injections, depending on risk group and CNS status. Cranial irradiation was omitted for all patients. Results: The overall 8-year event-free survival (EFS) and overall survival (OS) rates were 81.3% and 88.1%, respectively. In the CNS-1, TPL+, CNS-2, and CNS-3 groups, the 8-year EFS rates were 82.1%, 77.1%, 78.3%, and 57.4%, respectively. Multivariable analysis indicated that initial CNS-3 status, but not CNS-2 or TLP+, was an independent adverse predictor of outcome. The 8-year incidence of isolated CNS relapse was 1.7%
Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG hi... more Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG high ICOSLG expression at diagnosis is predictive for ALL relapse EGR3 and ICOSLG expressions are relapseassociated expression of ICOSLG on t(4;11) ALL cells leads to the rapid expansion of Tregs
Phase 2 study of lenalidomide in transfusion-dependent, low-risk, and intermediate-1 risk myelody... more Phase 2 study of lenalidomide in transfusion-dependent, low-risk, and intermediate-1 risk myelodysplastic syndromes with karyotypes other than deletion 5q. Blood, 111, 86-93.
PURPOSE We determined the prognostic factors and utility of allogeneic hematopoietic cell transpl... more PURPOSE We determined the prognostic factors and utility of allogeneic hematopoietic cell transplantation among children with newly diagnosed hypodiploid acute lymphoblastic leukemia (ALL) treated in contemporary clinical trials. PATIENTS AND METHODS This retrospective study collected data on 306 patients with hypodiploid ALL who were enrolled in the protocols of 16 cooperative study groups or institutions between 1997 and 2013. The clinical and biologic characteristics, early therapeutic responses as determined by minimal residual disease (MRD) assessment, treatment with or without MRD-stratified protocols, and allogeneic transplantation were analyzed for their impact on outcome. RESULTS With a median follow-up of 6.6 years, the 5-year event-free survival rate was 55.1% (95% CI, 49.3% to 61.5%), and the 5-year overall survival rate was 61.2% (95% CI, 55.5% to 67.4%) for the 272 evaluable patients. Negative MRD at the end of remission induction, high hypodiploidy with 44 chromosomes...
Background. EsPhALL2004 study showed a 10% advantage in disease-free survival for short, disconti... more Background. EsPhALL2004 study showed a 10% advantage in disease-free survival for short, discontinuous use of imatinib after induction in Philadelphia-chromosome-positive acute lymphoblastic leukaemia (ALL)Ph+ALL patients receiving BFM therapy and HSCT. Other contemporary studies showed an advantage from continuous protracted exposure to imatinib challenging the indications to transplant. The EsPhALL2010 study was designed to assess if imatinib given from day 15 of induction and continuously throughout chemotherapeutic treatment allowed to maintain or improve the outcome obtained in EsPhALL2004 despite decreasing the number of patients undergoing HSCT. Methods. Patients aged 1-17 years recruited into national frontline trials for acute lymphoblastic leukaemia and with t(9;22)(q34;q11) were eligible to the trial. Patients with abnormal renal or hepatic function, or an active systemic infection, were ineligible. Patients received imatinib 300/mg/m2 continuously from day 15 of induction, during chemotherapy. Minimal residual disease (MRD) was measured by IG/TR. Eligibility to HSCT depended on early morphological response and MRD. Imatinib was recommended throughout the first year after transplant. The co-primary endpoints were event-free survival and overall survival. Analyses included all patients enrolled (intention-to-treat population). The trial is registered with the European Clinical Trials Database
Germline anomalies of the INK4a-ARF and Cdk4 genes were sought in a series of 89 patients suspect... more Germline anomalies of the INK4a-ARF and Cdk4 genes were sought in a series of 89 patients suspected of having a genetic predisposition to melanoma. Patients were selected based on the following criteria: (a) familial melanoma (23 cases), (b) multiple primary melanoma (MPM; 18 cases), (c) melanoma and additional unrelated cancers (13 cases), (d) age at diagnosis less than 25 years (21 cases), and (e) nonphoto-induced melanoma (NPIM; 14 cases). Mutations of INK4a-ARF and Cdk4 were characterised by automated sequencing, and germline deletions of INK4a-ARF were also examined by real-time quantitative PCR. Seven germline changes of INK4a-ARF, five of which were novel, were found in seven patients (8%). Four were very likely to be pathogenic mutations and were found in three high-risk melanoma families and in a patient who had a pancreatic carcinoma in addition to melanoma. Three variants of uncertain significance were detected in one MPM patient, one patient <25 years, and one NPIM pa...
Competitive immunoglobulin/T-cell receptor polymerase-chain reaction (PCR) analysis with fluoresc... more Competitive immunoglobulin/T-cell receptor polymerase-chain reaction (PCR) analysis with fluorescent detection is a rapid, cheap and reproducible method for quantifying minimal residual disease (MRD), which is well adapted to the recognition of high-risk childhood acute lymphoblastic leukemia (ALL). We aimed at defining whether flow cytometry (FC) techniques can bypass limitations of PCR for MRD determination. We analyzed 140 remission samples from 91 patients using both competitive PCR amplification of antigen-receptor genes and four-color FC identification of leukemia immunophenotype. These methods were chosen with the aim of detecting at least 0.1% blasts. MRD was measured using both PCR and FC methods in 123 samples and the two methods provided concordant results in 119 of them (97%). Moreover, three out of the four discordant results appeared minor since MRD was detectable by both methods, but at different levels. In 12 of 13 samples from nine patients, mainly infants with earl...
Data on secondary acute lymphoblastic leukaemia (sALL) following ALL treatment are very rare. How... more Data on secondary acute lymphoblastic leukaemia (sALL) following ALL treatment are very rare. However, the incidence might be underestimated as sALLs without a significant lineage shift might automatically be diagnosed as relapses. Examination of immunoglobulin and T-cell receptor gene rearrangements brought a new tool that can help in discrimination between relapse and sALL. We focused on the recurrences of childhood ALL to discover the real frequency of the sALL after ALL treatment. We compared clonal markers in matched presentation and recurrence samples of 366 patients treated according to the Berlin-Frankfurt-Munster (BFM)-based protocols. We found two cases of sALL and another three, where the recurrence is suspicious of being sALL rather than relapse. Our proposal for the 'secondary ALL after ALL' diagnostic criteria is as follows: (A) No clonal relationship between diagnosis and recurrence; (B) significant immunophenotypic shift-significant cytogenetic shift-gain/loss of a fusion gene. For the sALL (A) plus at least one (B) criterion should be fulfilled. With these criteria, the estimated frequency of the sALL after ALL is according to our data 0.5-1.5% of ALL recurrences on BFMbased protocols. Finally, we propose a treatment strategy for the patients with secondary disease.
We present here the long-term results of three randomized clinical trials conducted on children w... more We present here the long-term results of three randomized clinical trials conducted on children with newly diagnosed acute lymphoblastic leukemia (ALL) between 1983 and 1998 by the Children Leukemia Cooperative Group (CLCG) from EORTC. In study 58831/32, the overall event-free survival (EFS) rates (± s.e.) at 6 and 10 years were 66% ± 1.8% and 65% ± 1.8%, respectively, and the risk of isolated central nervous system (CNS) relapse was 6% ± 1% and 7% ± 1%, respectively. In patients with a standard risk of relapse the omission of cyclophosphamide had no adverse effect on disease-free survival rates at 10 years (trial 58831). In medium-and high-risk patients the omission of radiotherapy did not increase the risk of CNS or systemic relapse (trial 58832). In study 58881 (1989-1998) the overall EFS rate at 8 years was 68.4% ± 1.2% and the risk of isolated CNS relapse was 4.2% ± 0.5%. In this trial which adressed three randomized questions, the following results were obtained: the combination of cytarabine at high doses with methotrexate at high doses during interval therapy did not improve prognosis. The addition of 6-mercaptopurine iv during maintenance increased the risk of late relapse. E. coli asparaginase was more toxic and has a higher efficacy than Erwinia asparaginase. Leukocyte counts Ͼ100 × 10 9 /l, specific genetic abnormalities, a poor initial response to steroids or a high level of minimal residual disease at early time points were consistently associated with an adverse prognosis in the 58881 trial.
Acute lymphoblastic leukemia (ALL) is a malignant disease of the white blood cells. The etiology ... more Acute lymphoblastic leukemia (ALL) is a malignant disease of the white blood cells. The etiology of ALL is believed to be multifactorial and likely to involve an interplay of environmental and genetic variables. We performed a genome-wide association study of 355 750 single-nucleotide polymorphisms (SNPs) in 474 controls and 419 childhood ALL cases characterized by a t(12;21)(p13;q22)-the most common chromosomal translocation observed in childhood ALL-which leads to an ETV6-RUNX1 gene fusion. The eight most strongly associated SNPs were followed-up in 951 ETV6-RUNX1-positive cases and 3061 controls from Germany/Austria and Italy, respectively. We identified a novel, genome-wide significant risk locus at 3q28 (TP63, rs17505102, P CMH ¼ 8.94 Â 10 À9 , OR ¼ 0.65). The separate analysis of the combined German/Austrian sample only, revealed additional genome-wide significant associations at 11q11 (OR8U8, rs1945213, P ¼ 9.14 Â 10 À11 , OR ¼ 0.69) and 8p21.3 (near INTS10, rs920590, P ¼ 6.12 Â 10 À9 , OR ¼ 1.36). These associations and another association at 11p11.2 (PTPRJ, rs3942852, P ¼ 4.95 Â 10 À7 , OR ¼ 0.72) remained significant in the German/Austrian replication panel after correction for multiple testing. Our findings demonstrate that germline genetic variation can specifically contribute to the risk of ETV6-RUNX1-positive childhood ALL. The identification of TP63 and PTPRJ as susceptibility genes emphasize the role of the TP53 gene family and the importance of proteins regulating cellular processes in connection with tumorigenesis.
Assessment of minimal residual disease (MRD) has acquired a prominent position in European treatm... more Assessment of minimal residual disease (MRD) has acquired a prominent position in European treatment protocols for patients with acute lymphoblastic leukemia (ALL), on the basis of its high prognostic value for predicting outcome and the possibilities for implementation of MRD diagnostics in treatment stratification. Therefore, there is an increasing need for standardization of methodologies and harmonization of terminology. For this purpose, a panel of representatives of all major European study groups on childhood and adult ALL and of international experts on PCR-and flow cytometry-based MRD assessment was built in the context of the Second International Symposium on MRD assessment in Kiel, Germany, 18-20 September 2008. The panel summarized the current state of MRD diagnostics in ALL and developed recommendations on the minimal technical requirements that should be fulfilled before implementation of MRD diagnostics into clinical trials. Finally, a common terminology for a standard description of MRD response and monitoring was established defining the terms 'complete MRD response', 'MRD persistence' and 'MRD reappearance'. The proposed MRD terminology may allow a refined and standardized assessment of response to treatment in adult and childhood ALL, and provides a sound basis for the comparison of MRD results between different treatment protocols.
Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG hi... more Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG high ICOSLG expression at diagnosis is predictive for ALL relapse EGR3 and ICOSLG expressions are relapseassociated expression of ICOSLG on t(4;11) ALL cells leads to the rapid expansion of Tregs
Juvenile myelomonocytic leukemia (JMML) treatment primarily relies on hematopoietic stem cell tra... more Juvenile myelomonocytic leukemia (JMML) treatment primarily relies on hematopoietic stem cell transplantation and results in long-term overall survival of 50-60%, demonstrating a need to develop novel treatments. Dysregulation of the non-coding RNA transcriptome has been demonstrated before in this rare and unique disorder of early childhood. In this study, we investigated the therapeutic potential of targeting overexpressed long non-coding RNAs (lncRNAs) in JMML. Total RNA sequencing of bone marrow and peripheral blood mononuclear cell preparations from 19 untreated JMML patients and three healthy children revealed 185 differentially expressed lncRNA genes (131 up-and 54 downregulated). LNA GapmeRs were designed for 10 overexpressed and validated lncRNAs. Molecular knockdown (≥ 70% compared to mock control) after 24 h of incubation was observed with two or more independent GapmeRs in 6 of them. For three lncRNAs (lnc-THADA-4, lnc-ACOT9-1 and NRIR) knockdown resulted in a significant decrease of cell viability after 72 h of incubation in primary cultures of JMML mononuclear cells, respectively. Importantly, the extent of cellular damage correlated with the expression level of the lncRNA of interest. In conclusion, we demonstrated in primary JMML cell cultures that knockdown of overexpressed lncRNAs such as lnc-THADA-4, lnc-ACOT9-1 and NRIR may be a feasible therapeutic strategy. Currently, hematopoietic stem cell transplantation (HSCT) is the established standard of care in juvenile myelomonocytic leukemia (JMML), a distinct myelodysplastic/myeloproliferative disorder of early childhood 1. HSCT results in long-term overall survival (OS) of approximately 50-60% of patients 2. Characteristic for JMML are proliferative features, such as monocytosis, splenomegaly, and a moderately elevated proportion of myeloblasts. These disease features are caused by clonal growth of an abnormal multipotent hematopoietic stem cell 3,4. In approximately 90-95% of patients, canonical mutations in the NRAS and KRAS (20-25%), PTPN11 (35%), NF1 (10-15%) or CBL (10-15%) genes are observed, strongly linking the disorder to hyperactivation of the RAS/ MAPK pathway. More recently, investigations of secondary mutations 5,6 , non-coding RNA expression 7,8 , and genomic DNA methylation 9-11 have led to a better understanding of the pathobiology of the disease. The acquisition of secondary mutations and aberrant DNA methylation were found to be associated with unfavorable clinical characteristics and poor prognosis, and might be used in the future to guide treatment decisions 5,12. Furthermore,
Juvenile myelomonocytic leukemia (JMML) is a rare aggressive myelodysplastic/myeloproliferative n... more Juvenile myelomonocytic leukemia (JMML) is a rare aggressive myelodysplastic/myeloproliferative neoplasm of early childhood, initiated by RAS-activating mutations. Genomic analyses have recently described JMML mutational landscape; however, the nature of JMML-propagating cells (JMML-PCs) and the clonal architecture of the disease remained until now elusive. Combining genomic (exome, RNA-seq), Colony forming assay and xenograft studies, we detect the presence of JMML-PCs that faithfully reproduce JMML features including the complex/nonlinear organization of dominant/minor clones, both at diagnosis and relapse. Further integrated analysis also reveals that although the mutations are acquired in hematopoietic stem cells, JMML-PCs are not always restricted to this compartment, highlighting the heterogeneity of the disease during the initiation steps. We show that the hematopoietic stem/progenitor cell phenotype is globally maintained in JMML despite overexpression of CD90/THY-1 in a subset of patients. This study shed new lights into the ontogeny of JMML, and the identity of JMML-PCs, and provides robust models to monitor the disease and test novel therapeutic approaches.
GATA2 deficiency French/Belgian cohort haematologica | 2018; 103(8) 1279 patients with nonsense o... more GATA2 deficiency French/Belgian cohort haematologica | 2018; 103(8) 1279 patients with nonsense or frameshift mutations (n=2 of 28). We also identify new features of the disease: acute lymphoblastic leukemia, juvenile myelomonocytic leukemia, fatal progressive multifocal leukoencephalopathy related to the JC virus, and immune/inflammatory diseases. A revised International Prognostic Scoring System (IPSS) score allowed a distinction to be made between a stable disease and hematologic transformation. Chemotherapy is of limited efficacy, and has a high toxicity with severe infectious complications. As the mortality rate is high in our cohort (up to 35% at the age of 40), hematopoietic stem cell transplantation (HSCT) remains the best choice of treatment to avoid severe infectious and/or hematologic complications. The timing of HSCT remains difficult to determine, but the earlier it is performed, the better the outcome.
KMT2A-rearranged acute lymphoblastic infant leukemia (KMT2A-r iALL) is associated with outsize ri... more KMT2A-rearranged acute lymphoblastic infant leukemia (KMT2A-r iALL) is associated with outsize risk of relapse and relapse mortality. We previously reported strong upregulation of the immediate early gene EGR3 in KMT2A::AFF1 iALL at relapse; now we provide analyses of the EGR3 regulome, which we assessed through binding and expression target analysis of an EGR3overexpressing t(4;11) cell culture model. Our data identify EGR3 as a regulator of early B-lineage commitment. Principal component analysis of 50 KMT2A-r iALL patients at diagnosis and 18 at relapse provided strictly dichotomous separation of patients based on the expression of four B-lineage genes. Absence of B-lineage gene expression translates to more than twofold poorer long-term event-free survival. In conclusion, our study presents four B-lineage genes with prognostic significance, suitable for gene expression-based risk stratification of KMT2A-r iALL patients.
Chromosomal rearrangements of the human KMT2A/MLL gene are associated with de novo as well as the... more Chromosomal rearrangements of the human KMT2A/MLL gene are associated with de novo as well as therapy-induced infant, pediatric, and adult acute leukemias. Here, we present the data obtained from 3401 acute leukemia patients that have been analyzed between 2003 and 2022. Genomic breakpoints within the KMT2A gene and the involved translocation partner genes (TPGs) and KMT2A-partial tandem duplications (PTDs) were determined. Including the published data from the literature, a total of 107 in-frame KMT2A gene fusions have been identified so far. Further 16 rearrangements were out-of-frame fusions, 18 patients had no partner gene fused to 5’-KMT2A, two patients had a 5’-KMT2A deletion, and one ETV6::RUNX1 patient had an KMT2A insertion at the breakpoint. The seven most frequent TPGs and PTDs account for more than 90% of all recombinations of the KMT2A, 37 occur recurrently and 63 were identified so far only once. This study provides a comprehensive analysis of the KMT2A recombinome in ...
To evaluate the prognostic significance of initial central nervous system (CNS) involvement of ch... more To evaluate the prognostic significance of initial central nervous system (CNS) involvement of children with acute lymphoblastic leukemia (ALL) enrolled in the EORTC 58951 trial. Patients and methods: From 1998 to 2008, 1930 ALL patients were included in the randomized EORTC 58951 trial. Overall treatment intensity was adjusted according to known prognostic factors including the level of minimal residual disease after induction treatment. CNS-directed therapy comprised four to 11 courses of i.v. methotrexate (5 g/m 2), and 10 to 19 intrathecal chemotherapy injections, depending on risk group and CNS status. Cranial irradiation was omitted for all patients. Results: The overall 8-year event-free survival (EFS) and overall survival (OS) rates were 81.3% and 88.1%, respectively. In the CNS-1, TPL+, CNS-2, and CNS-3 groups, the 8-year EFS rates were 82.1%, 77.1%, 78.3%, and 57.4%, respectively. Multivariable analysis indicated that initial CNS-3 status, but not CNS-2 or TLP+, was an independent adverse predictor of outcome. The 8-year incidence of isolated CNS relapse was 1.7%
Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG hi... more Early growth response 3 (EGR3) is a direct transactivator of the immune checkpoint gene ICOSLG high ICOSLG expression at diagnosis is predictive for ALL relapse EGR3 and ICOSLG expressions are relapseassociated expression of ICOSLG on t(4;11) ALL cells leads to the rapid expansion of Tregs
Phase 2 study of lenalidomide in transfusion-dependent, low-risk, and intermediate-1 risk myelody... more Phase 2 study of lenalidomide in transfusion-dependent, low-risk, and intermediate-1 risk myelodysplastic syndromes with karyotypes other than deletion 5q. Blood, 111, 86-93.
PURPOSE We determined the prognostic factors and utility of allogeneic hematopoietic cell transpl... more PURPOSE We determined the prognostic factors and utility of allogeneic hematopoietic cell transplantation among children with newly diagnosed hypodiploid acute lymphoblastic leukemia (ALL) treated in contemporary clinical trials. PATIENTS AND METHODS This retrospective study collected data on 306 patients with hypodiploid ALL who were enrolled in the protocols of 16 cooperative study groups or institutions between 1997 and 2013. The clinical and biologic characteristics, early therapeutic responses as determined by minimal residual disease (MRD) assessment, treatment with or without MRD-stratified protocols, and allogeneic transplantation were analyzed for their impact on outcome. RESULTS With a median follow-up of 6.6 years, the 5-year event-free survival rate was 55.1% (95% CI, 49.3% to 61.5%), and the 5-year overall survival rate was 61.2% (95% CI, 55.5% to 67.4%) for the 272 evaluable patients. Negative MRD at the end of remission induction, high hypodiploidy with 44 chromosomes...
Background. EsPhALL2004 study showed a 10% advantage in disease-free survival for short, disconti... more Background. EsPhALL2004 study showed a 10% advantage in disease-free survival for short, discontinuous use of imatinib after induction in Philadelphia-chromosome-positive acute lymphoblastic leukaemia (ALL)Ph+ALL patients receiving BFM therapy and HSCT. Other contemporary studies showed an advantage from continuous protracted exposure to imatinib challenging the indications to transplant. The EsPhALL2010 study was designed to assess if imatinib given from day 15 of induction and continuously throughout chemotherapeutic treatment allowed to maintain or improve the outcome obtained in EsPhALL2004 despite decreasing the number of patients undergoing HSCT. Methods. Patients aged 1-17 years recruited into national frontline trials for acute lymphoblastic leukaemia and with t(9;22)(q34;q11) were eligible to the trial. Patients with abnormal renal or hepatic function, or an active systemic infection, were ineligible. Patients received imatinib 300/mg/m2 continuously from day 15 of induction, during chemotherapy. Minimal residual disease (MRD) was measured by IG/TR. Eligibility to HSCT depended on early morphological response and MRD. Imatinib was recommended throughout the first year after transplant. The co-primary endpoints were event-free survival and overall survival. Analyses included all patients enrolled (intention-to-treat population). The trial is registered with the European Clinical Trials Database
Germline anomalies of the INK4a-ARF and Cdk4 genes were sought in a series of 89 patients suspect... more Germline anomalies of the INK4a-ARF and Cdk4 genes were sought in a series of 89 patients suspected of having a genetic predisposition to melanoma. Patients were selected based on the following criteria: (a) familial melanoma (23 cases), (b) multiple primary melanoma (MPM; 18 cases), (c) melanoma and additional unrelated cancers (13 cases), (d) age at diagnosis less than 25 years (21 cases), and (e) nonphoto-induced melanoma (NPIM; 14 cases). Mutations of INK4a-ARF and Cdk4 were characterised by automated sequencing, and germline deletions of INK4a-ARF were also examined by real-time quantitative PCR. Seven germline changes of INK4a-ARF, five of which were novel, were found in seven patients (8%). Four were very likely to be pathogenic mutations and were found in three high-risk melanoma families and in a patient who had a pancreatic carcinoma in addition to melanoma. Three variants of uncertain significance were detected in one MPM patient, one patient <25 years, and one NPIM pa...
Competitive immunoglobulin/T-cell receptor polymerase-chain reaction (PCR) analysis with fluoresc... more Competitive immunoglobulin/T-cell receptor polymerase-chain reaction (PCR) analysis with fluorescent detection is a rapid, cheap and reproducible method for quantifying minimal residual disease (MRD), which is well adapted to the recognition of high-risk childhood acute lymphoblastic leukemia (ALL). We aimed at defining whether flow cytometry (FC) techniques can bypass limitations of PCR for MRD determination. We analyzed 140 remission samples from 91 patients using both competitive PCR amplification of antigen-receptor genes and four-color FC identification of leukemia immunophenotype. These methods were chosen with the aim of detecting at least 0.1% blasts. MRD was measured using both PCR and FC methods in 123 samples and the two methods provided concordant results in 119 of them (97%). Moreover, three out of the four discordant results appeared minor since MRD was detectable by both methods, but at different levels. In 12 of 13 samples from nine patients, mainly infants with earl...
Data on secondary acute lymphoblastic leukaemia (sALL) following ALL treatment are very rare. How... more Data on secondary acute lymphoblastic leukaemia (sALL) following ALL treatment are very rare. However, the incidence might be underestimated as sALLs without a significant lineage shift might automatically be diagnosed as relapses. Examination of immunoglobulin and T-cell receptor gene rearrangements brought a new tool that can help in discrimination between relapse and sALL. We focused on the recurrences of childhood ALL to discover the real frequency of the sALL after ALL treatment. We compared clonal markers in matched presentation and recurrence samples of 366 patients treated according to the Berlin-Frankfurt-Munster (BFM)-based protocols. We found two cases of sALL and another three, where the recurrence is suspicious of being sALL rather than relapse. Our proposal for the 'secondary ALL after ALL' diagnostic criteria is as follows: (A) No clonal relationship between diagnosis and recurrence; (B) significant immunophenotypic shift-significant cytogenetic shift-gain/loss of a fusion gene. For the sALL (A) plus at least one (B) criterion should be fulfilled. With these criteria, the estimated frequency of the sALL after ALL is according to our data 0.5-1.5% of ALL recurrences on BFMbased protocols. Finally, we propose a treatment strategy for the patients with secondary disease.
We present here the long-term results of three randomized clinical trials conducted on children w... more We present here the long-term results of three randomized clinical trials conducted on children with newly diagnosed acute lymphoblastic leukemia (ALL) between 1983 and 1998 by the Children Leukemia Cooperative Group (CLCG) from EORTC. In study 58831/32, the overall event-free survival (EFS) rates (± s.e.) at 6 and 10 years were 66% ± 1.8% and 65% ± 1.8%, respectively, and the risk of isolated central nervous system (CNS) relapse was 6% ± 1% and 7% ± 1%, respectively. In patients with a standard risk of relapse the omission of cyclophosphamide had no adverse effect on disease-free survival rates at 10 years (trial 58831). In medium-and high-risk patients the omission of radiotherapy did not increase the risk of CNS or systemic relapse (trial 58832). In study 58881 (1989-1998) the overall EFS rate at 8 years was 68.4% ± 1.2% and the risk of isolated CNS relapse was 4.2% ± 0.5%. In this trial which adressed three randomized questions, the following results were obtained: the combination of cytarabine at high doses with methotrexate at high doses during interval therapy did not improve prognosis. The addition of 6-mercaptopurine iv during maintenance increased the risk of late relapse. E. coli asparaginase was more toxic and has a higher efficacy than Erwinia asparaginase. Leukocyte counts Ͼ100 × 10 9 /l, specific genetic abnormalities, a poor initial response to steroids or a high level of minimal residual disease at early time points were consistently associated with an adverse prognosis in the 58881 trial.
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Papers by Helene Cave