Author
Eric Delabesse
Other affiliations: Leipzig University, Paul Sabatier University, Paris Descartes University ...read more
Bio: Eric Delabesse is an academic researcher from University of Toulouse. The author has contributed to research in topics: Myeloid leukemia & Leukemia. The author has an hindex of 54, co-authored 207 publications receiving 20456 citations. Previous affiliations of Eric Delabesse include Leipzig University & Paul Sabatier University.
Papers published on a yearly basis
Papers
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French Institute of Health and Medical Research1, Hospital Research Foundation2, University of Freiburg3, Medical Research Council4, Utrecht University5, Harvard University6, Pasteur Institute7, Babraham Institute8, University of Paris9, Curie Institute10, National Institutes of Health11, University of Sydney12, Ludwig Maximilian University of Munich13, LSU Health Sciences Center New Orleans14
TL;DR: Retrovirus vector insertion can trigger deregulated premalignant cell proliferation with unexpected frequency, most likely driven by retrovirus enhancer activity on the LMO2 gene promoter.
Abstract: We have previously shown correction of X-linked severe combined immunodeficiency [SCID-X1, also known as gamma chain (gamma(c)) deficiency] in 9 out of 10 patients by retrovirus-mediated gamma(c) gene transfer into autologous CD34 bone marrow cells. However, almost 3 years after gene therapy, uncontrolled exponential clonal proliferation of mature T cells (with gammadelta+ or alphabeta+ T cell receptors) has occurred in the two youngest patients. Both patients' clones showed retrovirus vector integration in proximity to the LMO2 proto-oncogene promoter, leading to aberrant transcription and expression of LMO2. Thus, retrovirus vector insertion can trigger deregulated premalignant cell proliferation with unexpected frequency, most likely driven by retrovirus enhancer activity on the LMO2 gene promoter.
3,514 citations
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TL;DR: The BIOMED-2 multiplex tubes can now be used for diagnostic clonality studies as well as for the identification of PCR targets suitable for the detection of minimal residual disease.
Abstract: In a European BIOMED-2 collaborative study, multiplex PCR assays have successfully been developed and standardized for the detection of clonally rearranged immunoglobulin (Ig) and T-cell receptor (TCR) genes and the chromosome aberrations t(11;14) and t(14;18). This has resulted in 107 different primers in only 18 multiplex PCR tubes: three VH-JH, two DH-JH, two Ig kappa (IGK), one Ig lambda (IGL), three TCR beta (TCRB), two TCR gamma (TCRG), one TCR delta (TCRD), three BCL1-Ig heavy chain (IGH), and one BCL2-IGH. The PCR products of Ig/TCR genes can be analyzed for clonality assessment by heteroduplex analysis or GeneScanning. The detection rate of clonal rearrangements using the BIOMED-2 primer sets is unprecedentedly high. This is mainly based on the complementarity of the various BIOMED-2 tubes. In particular, combined application of IGH (VH-JH and DH-JH) and IGK tubes can detect virtually all clonal B-cell proliferations, even in B-cell malignancies with high levels of somatic mutations. The contribution of IGL gene rearrangements seems limited. Combined usage of the TCRB and TCRG tubes detects virtually all clonal T-cell populations, whereas the TCRD tube has added value in case of TCRgammadelta(+) T-cell proliferations. The BIOMED-2 multiplex tubes can now be used for diagnostic clonality studies as well as for the identification of PCR targets suitable for the detection of minimal residual disease.
2,902 citations
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TL;DR: These findings functionally specify a genetic network that controls growth in T cell progenitors and led to sustained remission in 3 of the 4 cases of T cell leukemia, but failed in the fourth.
Abstract: Previously, several individuals with X-linked SCID (SCID-X1) were treated by gene therapy to restore the missing IL-2 receptor gamma (IL2RG) gene to CD34+ BM precursor cells using gammaretroviral vectors. While 9 of 10 patients were successfully treated, 4 of the 9 developed T cell leukemia 31-68 months after gene therapy. In 2 of these cases, blast cells contained activating vector insertions near the LIM domain-only 2 (LMO2) proto-oncogene. Here, we report data on the 2 most recent adverse events, which occurred in patients 7 and 10. In patient 10, blast cells contained an integrated vector near LMO2 and a second integrated vector near the proto-oncogene BMI1. In patient 7, blast cells contained an integrated vector near a third proto-oncogene,CCND2. Additional genetic abnormalities in the patients' blast cells included chromosomal translocations, gain-of-function mutations activating NOTCH1, and copy number changes, including deletion of tumor suppressor gene CDKN2A, 6q interstitial losses, and SIL-TAL1 rearrangement. These findings functionally specify a genetic network that controls growth in T cell progenitors. Chemotherapy led to sustained remission in 3 of the 4 cases of T cell leukemia, but failed in the fourth. Successful chemotherapy was associated with restoration of polyclonal transduced T cell populations. As a result, the treated patients continued to benefit from therapeutic gene transfer.
1,667 citations
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TL;DR: The standardized RT-PCR protocol and primer sets can now be used for molecular classification of acute leukemia at diagnosis and for MRD detection during follow-up to evaluate treatment effectiveness.
Abstract: Prospective studies on the detection of minimal residual disease (MRD) in acute leukemia patients have shown that large-scale MRD studies are feasible and that clinically relevant MRD-based risk group classification can be achieved and can now be used for designing new treatment protocols. However, multicenter international treatment protocols with MRD-based stratification of treatment need careful standardization and quality control of the MRD techniques. This was the aim of the European BIOMED-1 Concerted Action 'Investigation of minimal residual disease in acute leukemia: international standardization and clinical evaluation' with participants of 14 laboratories in eight European countries (ES, NL, PT, IT, DE, FR, SE and AT). Standardization and quality control was performed for the three main types of MRD techniques, ie flow cytometric immunophenotyping, PCR analysis of antigen receptor genes, and RT-PCR analysis of well-defined chromosomal aberrations. This study focussed on the latter MRD technique. A total of nine well-defined chromosome aberrations with fusion gene transcripts were selected: t(1;19) with E2A-PBX1, t(4;11) with MLL-AF4, t(8;21) with AML1-ETO, t(9;22) with BCR-ABL p190 and BCR-ABL p210, t(12;21) with TEL-AML1, t(15;17) with PML-RARA, inv (16) with CBFB-MYH11, and microdeletion 1p32 with SIL-TAL1. PCR primers were designed according to predefined criteria for single PCR (external primers A B) and nested PCR (internal primers C D) as well as for 'shifted' PCR with a primer upstream (E5' primer) or downstream (E3' primer) of the external A B primers. The 'shifted' E primers were designed for performing an independent PCR together with one of the internal primers for confirmation (or exclusion) of positive results. Various local RT and PCR protocols were compared and subsequently a common protocol was designed, tested and adapted, resulting in a standardized RT-PCR protocol. After initial testing (with adaptations whenever necessary) and approval by two or three laboratories, the primers were tested by all participating laboratories, using 17 cell lines and patient samples as positive controls. This testing included comparison with local protocols and primers as well as sensitivity testing via dilution experiments. The collaborative efforts resulted in standardized primer sets with a minimal target sensitivity of 10-2 for virtually all single PCR analyses, whereas the nested PCR analyses generally reached the minimal target sensitivity of 10-4. The standardized RT-PCR protocol and primer sets can now be used for molecular classification of acute leukemia at diagnosis and for MRD detection during follow-up to evaluate treatment effectiveness.
1,170 citations
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TL;DR: The ABL gene is proposed to be used as CG for RQ-PCR-based diagnosis and MRD detection in leukemic patients and these data are not only eligible for quantifying of fusion gene transcripts, but also for the quantification of aberrantly expressed genes.
Abstract: Real-time quantitative RT-PCR (RQ-PCR) is a sensitive tool to monitor minimal residual disease (MRD) in leukemic patients through the amplification of a fusion gene (FG) transcript. In order to correct variations in RNA quality and quantity and to calculate the sensitivity of each measurement, a control gene (CG) transcript should be amplified in parallel to the FG transcript. To identify suitable CGs, a study group within the Europe Against Cancer (EAC) program initially focused on 14 potential CGs using a standardized RQ-PCR protocol. Based on the absence of pseudogenes and the level and stability of the CG expression, three genes were finally selected: Abelson (ABL), beta-2-microglobulin (B2M), and beta-glucuronidase (GUS). A multicenter prospective study on normal (n=126) and diagnostic leukemic (n=184) samples processed the same day has established reference values for the CG expression. A multicenter retrospective study on over 250 acute and chronic leukemia samples obtained at diagnosis and with an identified FG transcript confirmed that the three CGs had a stable expression in the different types of samples. However, only ABL gene transcript expression did not differ significantly between normal and leukemic samples at diagnosis. We therefore propose to use the ABL gene as CG for RQ-PCR-based diagnosis and MRD detection in leukemic patients. Overall, these data are not only eligible for quantification of fusion gene transcripts, but also for the quantification of aberrantly expressed genes.
894 citations
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TL;DR: Circos uses a circular ideogram layout to facilitate the display of relationships between pairs of positions by the use of ribbons, which encode the position, size, and orientation of related genomic elements.
Abstract: We created a visualization tool called Circos to facilitate the identification and analysis of similarities and differences arising from comparisons of genomes. Our tool is effective in displaying variation in genome structure and, generally, any other kind of positional relationships between genomic intervals. Such data are routinely produced by sequence alignments, hybridization arrays, genome mapping, and genotyping studies. Circos uses a circular ideogram layout to facilitate the display of relationships between pairs of positions by the use of ribbons, which encode the position, size, and orientation of related genomic elements. Circos is capable of displaying data as scatter, line, and histogram plots, heat maps, tiles, connectors, and text. Bitmap or vector images can be created from GFF-style data inputs and hierarchical configuration files, which can be easily generated by automated tools, making Circos suitable for rapid deployment in data analysis and reporting pipelines.
8,315 citations
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TL;DR: The classification of myeloid neoplasms and acute leukemia is highlighted with the aim of familiarizing hematologists, clinical scientists, and hematopathologists not only with the major changes in the classification but also with the rationale for those changes.
4,274 citations
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University of Ulm1, Fred Hutchinson Cancer Research Center2, King's College London3, University of Rome Tor Vergata4, University of Münster5, Brigham and Women's Hospital6, University of Chicago7, Memorial Sloan Kettering Cancer Center8, Leipzig University9, VU University Amsterdam10, University of Valencia11, National Taiwan University12, Monash University13, Alfred Hospital14, Erasmus University Medical Center15, Ohio State University16
TL;DR: An international panel to provide updated evidence- and expert opinion-based recommendations for diagnosis and management of acute myeloid leukemia in adults includes a revised version of the ELN genetic categories, a proposal for a response category based on MRD status, and criteria for progressive disease.
4,066 citations
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Washington University in St. Louis1, Brown University2, University of British Columbia3, University of North Carolina at Chapel Hill4, University of Southern California5, Massachusetts Institute of Technology6, Seattle Cancer Care Alliance7, Johns Hopkins University8, University of Texas MD Anderson Cancer Center9, Nationwide Children's Hospital10, National Institutes of Health11, SRA International12, Temple University13, University of Chicago14, University of Pennsylvania15
TL;DR: It is found that a complex interplay of genetic events contributes to AML pathogenesis in individual patients and the databases from this study are widely available to serve as a foundation for further investigations of AMl pathogenesis, classification, and risk stratification.
Abstract: BACKGROUND—Many mutations that contribute to the pathogenesis of acute myeloid leukemia (AML) are undefined The relationships between patterns of mutations and epigenetic phenotypes are not yet clear METHODS—We analyzed the genomes of 200 clinically annotated adult cases of de novo AML, using either whole-genome sequencing (50 cases) or whole-exome sequencing (150 cases), along with RNA and microRNA sequencing and DNA-methylation analysis RESULTS—AML genomes have fewer mutations than most other adult cancers, with an average of only 13 mutations found in genes Of these, an average of 5 are in genes that are recurrently mutated in AML A total of 23 genes were significantly mutated, and another 237 were mutated in two or more samples Nearly all samples had at least 1 nonsynonymous mutation in one of nine categories of genes that are almost certainly relevant for pathogenesis, including transcriptionfactor fusions (18% of cases), the gene encoding nucleophosmin (NPM1) (27%), tumorsuppressor genes (16%), DNA-methylation–related genes (44%), signaling genes (59%), chromatin-modifying genes (30%), myeloid transcription-factor genes (22%), cohesin-complex genes (13%), and spliceosome-complex genes (14%) Patterns of cooperation and mutual exclusivity suggested strong biologic relationships among several of the genes and categories CONCLUSIONS—We identified at least one potential driver mutation in nearly all AML samples and found that a complex interplay of genetic events contributes to AML pathogenesis in individual patients The databases from this study are widely available to serve as a foundation for further investigations of AML pathogenesis, classification, and risk stratification (Funded by the National Institutes of Health) The molecular pathogenesis of acute myeloid leukemia (AML) has been studied with the use of cytogenetic analysis for more than three decades Recurrent chromosomal structural variations are well established as diagnostic and prognostic markers, suggesting that acquired genetic abnormalities (ie, somatic mutations) have an essential role in pathogenesis 1,2 However, nearly 50% of AML samples have a normal karyotype, and many of these genomes lack structural abnormalities, even when assessed with high-density comparative genomic hybridization or single-nucleotide polymorphism (SNP) arrays 3-5 (see Glossary) Targeted sequencing has identified recurrent mutations in FLT3, NPM1, KIT, CEBPA, and TET2 6-8 Massively parallel sequencing enabled the discovery of recurrent mutations in DNMT3A 9,10 and IDH1 11 Recent studies have shown that many patients with
3,980 citations
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University of Ulm1, University of Rome Tor Vergata2, Fred Hutchinson Cancer Research Center3, University of Münster4, University of Wales5, University of Chicago6, Nagoya University7, Leipzig University8, VU University Medical Center9, Northwestern University10, Erasmus University Medical Center11, Ohio State University12
TL;DR: An international expert panel is provided to provide updated evidence- and expert opinion-based recommendations for the diagnosis and management of AML, that contain both minimal requirements for general practice as well as standards for clinical trials.
3,000 citations