Publications by authors named "Louwagie A"

Epitranscriptomics, the study of chemical modifications of RNA molecules, is increasingly recognized as an important component of gene expression regulation. While the majority of research has focused on N-methyladenosine (mA) RNA methylation on mRNAs, emerging evidence has revealed that the mA modification extends beyond mRNAs to include chromatin-associated RNAs (caRNAs). CaRNAs constitute an important class of RNAs characterized by their interaction with the genome and epigenome.

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The pediatric extra-cranial tumor neuroblastoma displays a low mutational burden while recurrent copy number alterations are present in most high-risk cases. Here, we identify SOX11 as a dependency transcription factor in adrenergic neuroblastoma based on recurrent chromosome 2p focal gains and amplifications, specific expression in the normal sympatho-adrenal lineage and adrenergic neuroblastoma, regulation by multiple adrenergic specific (super-)enhancers and strong dependency on high SOX11 expression in adrenergic neuroblastomas. SOX11 regulated direct targets include genes implicated in epigenetic control, cytoskeleton and neurodevelopment.

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The NFIA-ETO2 fusion is the product of a t(1;16)(p31;q24) chromosomal translocation, so far, exclusively found in pediatric patients with pure erythroid leukemia (PEL). To address the role for the pathogenesis of the disease, we facilitated the expression of the NFIA-ETO2 fusion in murine erythroblasts (EBs). We observed that NFIA-ETO2 significantly increased proliferation and impaired erythroid differentiation of murine erythroleukemia cells and of primary fetal liver-derived EBs.

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High-risk neuroblastoma, a pediatric tumor originating from the sympathetic nervous system, has a low mutation load but highly recurrent somatic DNA copy number variants. Previously, segmental gains and/or amplifications allowed identification of drivers for neuroblastoma development. Using this approach, combined with gene dosage impact on expression and survival, we identified ribonucleotide reductase subunit M2 (RRM2) as a candidate dependency factor further supported by growth inhibition upon in vitro knockdown and accelerated tumor formation in a neuroblastoma zebrafish model coexpressing human RRM2 with MYCN.

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Ring-opening polymerization of five lactones catalyzed by Candida antarctica lipase B in ionic liquids yielded poly(hydroxyalkanoates) of moderate molecular weights up to Mn=13,000. In the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethane)-sulfonimide and with a low weight ratio of enzyme to lactone (1:100) we obtained polymers from beta-propiolactone, delta-valerolactone, and epsilon-caprolactone with degrees of polymerization as high as 170, 25, and 85, respectively; oligomers from beta-butyrolactone and gamma-butyrolactone with degrees of polymerization of 5; and a copolymer of beta-propiolactone and beta-butyrolactone with a degree of polymerization of 180. Water-immiscible ionic liquids were superior to water-miscible ionic liquids.

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A 13-year-old girl with chronic anaemia showed features of congenital dyserythropoietic anaemia (CDA) type II. The main clinical and haematological findings were splenomegaly, a mild microcytic anaemia, and numerous bizarre and binucleate normoblasts in the bone marrow. The acidified serum lysis test (Ham's test) performed with 5 normal sera was positive.

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Bone marrow and peripheral blood from a myelodysplastic syndrome patient with trisomy 13 and monoclonal B lymphocytes (without evidence of systemic lymphoma) were investigated for clonal lymphoid lineage involvement using interphase fluorescence in situ hybridization (FISH) and X-chromosome inactivation assay (HUMARA) on CD19+ and CD34+ sorted cells. Trisomy 13 was detected in 55% of CD34+ cells and in 5.5% of CD19+ cells, the latter being comparable to the negative control specimen.

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Achieving a complete cytogenetic response (CCgR) is a major target in the treatment of chronic myeloid leukemia (CML) with interferon-alpha (IFN-alpha), but CCgRs are rare. The mean CCgR rate is 13%, in a range of 5% to 33%. A collaborative study of 9 European Union countries has led to the collection of data on 317 patients who were first seen between 1983 and 1997 and achieved CCgRs with IFN-alpha alone or in combination with hydroxyurea.

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Three cases of low-grade B-cell non-Hodgkin's lymphoma associated with cold agglutinin syndrome, cytogenetically characterized by partial trisomy 3, are presented in this report. Our data suggest that the long arm of chromosome 3 might be of particular importance in the pathogenesis of this subgroup of lymphomas.

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Clinical, cytogenetic, fluorescence in situ hybridization (FISH), and Southern blot data of 18 patients with different subtypes of B-cell non-Hodgkin's lymphoma, cytogenetically characterized by partial trisomy 12, are presented. These chromosomal changes occurred predominantly in clinically progressive chronic lymphocytic leukemia, mixed cell type, and advanced-stage follicle center cell lymphoma at the time of relapse or transformation into diffuse large cell lymphoma. Partial trisomy 12 consistently included the long arm of chromosome 12, either completely or partially, and resulted from dup(12q) or other rearrangements involving chromosome 12.

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We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low-risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I-II), usually required immediate treatment and their survival was shorter.

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Background: Little is known about the morphological and clinical features of the minority of acute myeloid leukemias (AML) that carry the t(9;22)(q34;q11) translocation.

Materials And Methods: Cytologic, cytogenetic and clinical features were studied at diagnosis and during disease evolution in 11 patients presenting with de novo AML. Diagnoses according to the FAB criteria were AML-M2 (3 cases), AML-MO and AML-M4 (2 cases each), AML-M4eos, AML-M5, AML-M6, AML-M7 (1 case each).

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We report three cases of myeloid disorders with a dic(1;15)(p11;p11), resulting in trisomy of the long arm of chromosome 1. A review of the literature showed six cases, reported as t(1;15). We suggest that these cases have the same anomaly and should be reappraised as dic(1;15).

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Clinical and cytogenetic data were analysed in 54 patients with acute non-lymphocytic leukaemias (ANLL) or MDS (myelodysplastic syndromes) and deletion of the long arm of chromosome 7 (7q-), in order to determine if there is a commonly deleted region in 7q and to establish possible correlations between karyotypic features, such as karyotype pattern, karyotype complexity, associated anomalies, and/or the type of deleted segments, and outcome of patients with these disorders. The median follow-up of our patients was 4 months (range 1-89), as was the median survival. In 30% of the cases there was a history of preceding MDS or previous chemotherapy.

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Translocation t(14;19)(q32;q13) is a rare but recurrent abnormality in chronic lymphocytic leukemia and small cell lymphoma. It has been associated with rearrangements of the BCL3 gene, which is located at the breakpoint on chromosome 19 and is juxtaposed to the immunoglobulin heavy chain locus on chromosome 14 as a result of the translocation. This results in transcriptional up-regulation of the BCL3 gene, which encodes a transcription coactivator, an I-kappa B protein, probably contributing to disease progression.

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609 patients with B cell chronic lymphoproliferative disorder were studied with the primary aim of analyzing the cytogenetic profile of B cell chronic lymphocytic leukemias and, if possible, define correlations with FAB classification of these diseases. Morphological and immunological studies were performed according to criteria proposed by the FAB group. A panel of monoclonal antibodies, including at least sIg, CD19, CD5, and FMC7 was used.

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Idic(X)(q13) represents a rare but recurrent chromosomal abnormality in haematological malignancies. We present five new cases characterized by this particular aberration and review the literature on this subject. The patients were elderly females with a diagnosis of refractory anaemia (1/5), refractory anaemia with ringed sideroblasts (2/5), chronic myelomonocytic leukaemia (1/5), and Philadelphia chromosome-negative chronic myeloid leukaemia (1/5).

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Cold-antibody autoimmune haemolytic anaemia is a rare entity that has been associated with a wide variety of pathological processes, including malignant lymphoproliferative disorders. In this retrospective study we recorded, as far as possible, clinical, haematological, immunological, morphological, pathological, cytogenetic and molecular data on 10 patients with cold agglutinin disease (CAD). Cytogenetic anomalies were found in four cases in which an underlying lymphoma could be evidenced.

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Mediastinal large-B-cell lymphoma with sclerosis is now considered to be a discrete subtype of lymphoma. It probably originates in the thymus, a T-cell organ. Early publications consider this lymphoma as an aggressive disorder with poor prognosis.

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T-cells are only rarely involved in chronic myeloid leukemia. We report an unusual case of T-lymphoid extramedullary (lymphadenopathic) blast crisis in a 66-year-old patient with Philadelphia positive chronic myeloid leukemia. The lymph node morphological picture resembled that of a peripheral T-cell lymphoma.

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