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D Leroux

Publications and source records attributed to D Leroux.

At least 19 recordsLinked to original sources
PubMed2006

Clinical, cytogenetic and molecular characteristics of 14 T-ALL patients carrying the TCRbeta-HOXA rearrangement: a study of the Groupe Francophone de Cytogénétique Hématologique.

Recently, we and others described a new chromosomal rearrangement, that is, inv(7)(p15q34) and t(7;7)(p15;q34) involving the T-cell receptor beta (TCRbeta) (7q34) and the HOXA gene locus (7p15) in 5% of T-cell acute lymphoblastic leukemia (T-ALL) patients leading to transcriptional activation of especially HOXA10. To further address the clinical, immunophenotypical and molecular genetic findings of this chromosomal aberration, we studied 330 additional T-ALLs. This revealed TCRbeta-HOXA rearrangements in five additional patients, which brings the total to 14 cases in 424 patients (3.3%). Real-time quantitative PCR analysis for HOXA10 gene expression was performed in 170 T-ALL patients and detected HOXA10 overexpression in 25.2% of cases including all the cases with a TCRbeta-HOXA rearrangement (8.2%). In contrast, expression of the short HOXA10 transcript, HOXA10b, was almost exclusively found in the TCRbeta-HOXA rearranged cases, suggesting a specific role for the HOXA10b short transcript in TCRbeta-HOXA-mediated oncogenesis. Other molecular and/or cytogenetic aberrations frequently found in subtypes of T-ALL (SIL-TAL1, CALM-AF10, HOX11, HOX11L2) were not detected in the TCRbeta-HOXA rearranged cases except for deletion 9p21 and NOTCH1 activating mutations, which were present in 64 and 67%, respectively. In conclusion, this study defines TCRbeta-HOXA rearranged T-ALLs as a distinct cytogenetic subgroup by clinical, immunophenotypical and molecular genetic characteristics.

Adolescent↗
PubMed2006

[CDKN2A gene mutation and loss of p16 protein activity in a patient on levodopa presenting sporadic multiple primary melanoma].

BACKGROUND: Cutaneous melanoma is a complex disease involving genetic and environmental factors. Levodopa has been incriminated in the development and/or progression of melanoma. OBSERVATION: We report the case of a man treated with levodopa and a dopadecarboxylase inhibitor for Parkinson's disease and presenting 22 cutaneous melanomas over a 4-year period. The patient is of phototype II and presents multiple nevi. Genetic analysis of predisposing genes demonstrated a CDKN2A mutation with loss of p16 activity. DISCUSSION: Multiple melanomas may be associated with genetic predisposition, and screening for the latter should be performed. The exceptionally high number of melanomas developed by our patient raised suspicions about levodopa, a precursor in melanin synthesis, as a potential inducer. Increased dermatologic controls and screening for predisposing genetic factors appear to us to be warranted in the event of melanoma development in patients on levodopa.

Antiparkinson Agents↗
PubMed2003

[Genetic changes in chronic lymphocytic leukemia].

Chronic B-cell leukemias (CLL) are characterised by a striking cytogenetic signature composed of multiple recurrent chromosomal imbalances involving specific chromosomal regions i.e. 13q, 11q, 12q, 17p et 6q (decreasing order of frequency). These chromosomal aberrations may be found in up to 80% of the cases either as isolated or associated anomalies. They can also appear during the course of the disease suggesting their secondary nature. Furthermore, and at variance with other B-cell proliferations like lymphomas or myelomas, balanced translocations involving immunoglobulin (Ig) gene locus are rare. In addition to their interest in patient diagnosis and follow-up, these tumour-specific genetic markers also harbor important prognostic significance : isolated 13q deletions correlate with prolonged survival whereas both 17p and 11q partial deletions are independent predictors of rapid disease progression and short survival times in multivariate analyses. Genetic analyses as well as the first transcriptome studies of CLL reveal 1) a common mechanism of transformation and/or cell of origin, 2) the existence of at least two prognostic subgroups based on Ig mutational status.

Chromosome Aberrations↗
PubMed2001

Hypodiploidy is a major prognostic factor in multiple myeloma.

Conventional karyotypes performed before any treatment in 208 patients with multiple myeloma were reviewed by the Groupe Français de Cytogénétique Hématologique. A total of 138 patients displayed complex chromosomal abnormalities (CCAs). According to the chromosome number pattern, a first group of 75 patients had a hyperdiploid karyotype. A second group of 63 patients referred to as the hypodiploid group had either pseudodiploid, hypodiploid, or near-tetraploid karyotypes. Of 159 treated patients available for survival analysis, 116 had an abnormal karyotype. The comparison of overall survival (OS) between hyperdiploid and hypodiploid patients showed a highly significant difference (median OS 33.8 vs 12.6 months, respectively, P <.001). The presence of 14q32 rearrangements (36 of 116 patients) worsened the prognosis (median OS 17.6 vs 29.9 months, P <.02). The presence of chromosome 13q abnormalities (13qA, 63 patients) did not modify OS in CCA patients (median OS 20.6 vs 27.8 months, P <.59). However, taking into account the whole series including normal karyotypes, 13qA (63 of 159 patients) had a significant impact on OS (median 20.6 vs 37.1 months, P <.04). In the same way, the presence of a hypodiploid karyotype (52 of 159 patients) had a strong prognostic value (OS 12.8 vs 44.5 months, P <.000 01). A multivariate analysis including stage, beta2-microglobulin, bone marrow plasmocytosis, treatment type, 13qA, and hyperdiploidy and hypodiploidy showed that a hypodiploid karyotype was the first independent factor for OS (P <.001), followed by treatment approach. These results confirm that the chromosome number pattern of malignant plasma cells is a very powerful prognostic factor in newly diagnosed multiple myeloma patients.

Adult↗
PubMed2001

Novel evidence of a role for chromosome 1 pericentric heterochromatin in the pathogenesis of B-cell lymphoma and multiple myeloma.

1q rearrangement is a remarkably frequent secondary chromosomal change in both non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM), where it is associated with tumor progression. To gain insight into 1q rearrangement-associated disease mechanisms, we used fluorescence in situ hybridization (FISH) to search for recurring 1q breaks in 35 lymphoma samples (31 NHL patients and 4 lymphoma-derived cell lines) as well as 22 MM patients with cytogenetically determined 1q abnormalities. Strikingly, dual-color FISH analysis with chromosome 1 centromere and 1q12-specific probes identified constitutive heterochromatin band 1q12 as the single most frequent breakpoint site in both NHL and MM (39% and 89% of 1q breaks, respectively). These rearrangements consistently generated aberrant heterochromatin/euchromatin junctions and gain of 1q12 material. A further 30% of NHL 1q breaks specifically involved two other novel, closely spaced sites (clusters I and II) within a 2.5 Mb region of proximal 1q21 (D1S3620 to D1S3623). A possible association between these sites and NHL subtype was evident; the cluster I rearrangement was frequent in follicular and diffuse large cell lymphoma, whereas the cluster II rearrangement was more frequently observed in diffuse small-cell lymphoma (2/2 marginal zone lymphomas, 1/2 atypical chronic lymphocytic leukemias, and 1 lymphoplasmacytic lymphoma in this series). Candidate oncogenes bordering this interval (BCL9 and AF1Q) were not rearranged in any patient except one (AF1Q). This study provides the first evidence of involvement of 1q12 constitutive heterochromatin in the pathogenesis of NHL and MM and indicates proximal 1q21 to be of specific pathological significance in NHL.

Adult↗
PubMed2001

Dag-1 carcinoma cell in studying the mechanisms of progression and therapeutic resistance in bladder cancer.

OBJECTIVE: We describe a new human bladder carcinoma cell line (DAG-1) established from a resected bladder cancer fragment and maintained in culture for more than 5 years and over 300 passages. METHODS AND RESULTS: Immunological, biochemical and molecular analysis showed that the DAG-1 cells (62 chromosomes) express the cytokeratines 8, 13, 18 and 20 that confirm their epithelial origin as well as numerous cytokine and cytokine receptor mRNAs. They secrete tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitors (PAI-1 and PAI-2), and express u-PA receptors (u-PAR/CD87) at their surface. DAG-1 cells are resistant to TNFalpha- and IFNgamma-induced apoptosis, two cytokines secreted in the urine of Calmette-Guérin bacillus-treated patients and involved in the tumor regression. CONCLUSION: The DAG-1 cell line is a useful tool, both in vitro and in vivo, to study the progression of bladder tumors and their mechanisms of resistance to immunotherapy in relation with PAI-2 and antioxidant enzymes.

Aged↗
PubMed2000

The IgG Fc receptor, FcgammaRIIB, is a target for deregulation by chromosomal translocation in malignant lymphoma.

Rearrangement of chromosomal bands 1q21-23 is one of the most frequent chromosomal aberrations observed in hematological malignancy. The genes affected by these rearrangements remain poorly characterized. Typically, 1q21-23 rearrangements arise during tumor evolution and accompany disease-specific chromosomal rearrangements such as t(14;18) (BCL2) and t(8;14) (MYC), where they are thus thought to play an important role in tumor progression. The pathogenetic basis of this 1q21-23-associated disease progression is currently unknown. In this setting, we surveyed our series of follicular lymphoma for evidence of recurring 1q21-23 breaks and identified three cases in which a t(14;18)(q32;q21) was accompanied by a novel balanced t(1;22)(q22;q11). Molecular cloning of the t(1;22) in a cell line (B593) derived from one of these cases and detailed fluorescent in situ hybridization mapping in the two remaining cases identified the FCGR2B gene, which encodes the immunoreceptor tyrosine-based inhibition motif-bearing IgG Fc receptor, FcgammaRIIB, as the target gene of the t(1;22)(q22;q11). We demonstrate deregulation of FCGR2B leading to hyperexpression of FcgammaRIIb2 as the principal consequence of the t(1;22). This is evidence that IgG Fc receptors can be targets for deregulation through chromosomal translocation in lymphoma. It suggests that dysregulation of FCGR2B may play a role in tumor progression in follicular lymphoma.

Animals↗
PubMed1999

Role of autologous CD4+ T cell clones in human B non-Hodgkin's lymphoma: aborted activation and G1 blockade induced by cell-cell contact.

This article describes the study of the functional relationship between auto-tumor-reactive CD4(+) T cell clones (TCC) and autologous malignant B cells. Four auto-tumor-reactive CD4(+) TCC were derived from tumor-infiltrating T lymphocytes (TIL-T) from a freshly isolated human follicular lymphoma by the following technique: total CD4(+) TIL-T were negatively purified by an immunomagnetic procedure, then CD4(+) TCC were obtained by limiting dilution in the presence of IL-2 and autologous non-irradiated follicular lymphoma cells as feeders. After expansion, these CD4(+) TCC were co-cultured with non-irradiated autologous malignant B cells. All four TCC were activated by B lymphoma cells and proliferated, as assessed by CD25 expression and cell cycle analysis. Activation and proliferation of B lymphoma cells were studied in response to activated CD4(+) T cells. Although all four TCC were able to induce B lymphoma cell activation (Ki-67 antigen induction and CD40 up-regulation), cells were subsequently blocked in G1 phase. Activation of B-NHL cells was mediated by TCR-HLA class II interaction, as shown by a blocking experiment using an anti-CD4 monoclonal antibody (mAb). Since anti-CD40 mAb with or without IL-4 did not induce proliferation of B lymphoma cells in contrast to normal B cells, we suggest that the blockade in G1 phase is due to the presence of abnormalities in B lymphoma cells. This is the first evidence that autologous reactive CD4(+) TCC can engage follicular lymphoma B cells to enter the cell cycle and induce an aborted activation stage.

Antibodies, Monoclonal↗
PubMed1999

Deletion 7q in B-cell low-grade lymphoid malignancies: a cytogenetic/fluorescence in situ hybridization and immunopathologic study.

Ten cases presenting a simple karyotype and del(7q) as a primary event were selected out of 353 patients referred as B-cell low-grade malignant lymphoproliferative disorders. Chromosome 7-specific painting probes confirmed the deletion that was tentatively assigned to bands q31q35. Chromosome 7 was involved in an interstitial deletion in seven cases, in an unbalanced translocation in two cases, and in a ring chromosome in one case. Common clinical/hematological features included advanced age, marked splenomegaly, and peripheral blood monoclonal IgM(D) lymphocytosis. Regardless of morphologic entity, most cases shared lymphoplasmacytoid features. Deletion 7q may delineate a variety of low-grade B-cell lymphoid disorders characterized by a common clinical history and immunopathologic similarities. The cytogenetic pattern and the ongoing work on molecular mapping of this deletion suggest that the loss of a putative tumor-supressor gene at 7q31q32 may constitute an early event in their pathogenesis.

Age Factors↗
PubMed1999

Interphase FISH: a rapid method for detecting malignant plasma cells in multiple myeloma patients submitted to autologous transplantation.

Fluorescence in situ hybridization (FISH) on interphase nuclei has been shown to be an efficient method for detecting aneuploidy in multiple myeloma (MM). The aim of this study was to test the feasibility of FISH techniques for detecting malignant cells in the harvests of MM patients submitted to autologous transplantation. As trisomy 9 (T9) is a frequent event in MM, we used it as a genetic marker of malignant plasma cells. T9 was detected in 45 out of 55 MM bone marrow samples (81.8%) using a chromosome 9 centromeric (C9C) probe. Twenty-four of the 55 MM patients were subjected to high-dose therapy followed by autologous unselected progenitor cell transplantation. Trisomy 9 was detected in 20 patients and was used as a marker of malignant cells. Upon karyotypic analysis, three of the four remaining patients without T9 showed an unbalanced translocation leading to a complete trisomy of the long arm of chromosome 1 (T1q). We thus used a 1q juxtacentromeric probe, pUC1.77, as another genetic marker of malignant plasma cells in these three further patients. FISH with C9C or pUC1.77 probes was performed on the harvests of these 23 patients and detected clonal cells in 11 transplants. The disease-free survival from graft was significantly longer for the patients who had no malignant cells in their transplant (P=0.009). The median disease-free survival was 23 months in these patients, as compared to 12 months in the patients whose transplant was contaminated. As almost all MM are cytogenetically abnormal, FISH with adequate probes represents a simple, quantitative tool for rapid detection of malignant cells in the harvests. Our results also suggest that the presence of MM cells in the transplant may be predictive of poor outcome.

Adult↗
PubMed1999

Human herpesvirus 8 and Epstein Barr-virus in a cutaneous B-cell lymphoma and a malignant cell line established from the blood of an AIDS patient.

Human Herpesvirus 8 (HHV-8) has been consistently associated with Primary Effusion Lymphoma (PEL or body-cavity-based lymphoma) but not with other lymphomas. This paper reports on an AIDS patient without obvious malignant effusion in body cavities but with a cutaneous lymphoma where HHV-8 and Epstein-Barr virus (EBV) were detected by PCR and electron microscopy. Both viruses were also detected in all the cells of a malignant cell line (BBG1) established from the patient's peripheral blood mononuclear cells. As in PEL and PEL-derived cell lines, both the tumor and the lines lacked B-antigen expression in immunological studies but were of the same B origin as shown by clonal immunoglobulin gene rearrangements. In contrast to other co-infected cell lines, BBG1 and subclones spontaneously expressed the HHV-8 lytic antigens p40, p27, p60 and the EBV transforming latent antigen EBNA2. These data suggest that the clinical and biological features of HHV-8-and EBV-associated lymphomas could be wider than has been described to date in PEL particularly with the in vivo presence of circulating malignant dually-infected cells engaged in a spontaneous HHV-8 lytic infection.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Fibroblast growth factor receptor 1 is fused to FIM in stem-cell myeloproliferative disorder with t(8;13).

Chromosome 8p11-12 is the site of a recurrent breakpoint in a myeloproliferative disorder that involves lymphoid (T- or B-cell), myeloid hyperplasia and eosinophilia, and evolves toward acute leukemia. This multilineage involvement suggests the malignant transformation of a primitive hematopoietic stem cell. In this disorder, the 8p11-12 region is associated with three different partners 6q27, 9q33, and 13q12. We describe here the molecular characterization of the t(8;13) translocation that involves the FGFR1 gene from 8p12, encoding a tyrosine kinase receptor for members of the fibroblast growth factor family, and a gene from 13q12, tentatively named FIM (Fused In Myeloproliferative disorders). FIM is related to DXS6673E, a candidate gene for X-linked mental retardation in Xq13.1; this defines a gene family involved in different human pathologies. The two reciprocal fusion transcripts, FIM/FGFR1 and FGFR1/FIM are expressed in the malignant cells. The FIM/FGFR1 fusion protein contains the FIM putative zinc finger motifs and the catalytic domain of FGFR1. We show that it has a constitutive tyrosine kinase activity.

3T3 Cells↗
PubMed1998

t(6;8), t(8;9) and t(8;13) translocations associated with stem cell myeloproliferative disorders have close or identical breakpoints in chromosome region 8p11-12.

A stem-cell myeloproliferative disorder involving T- and B-cell, and myeloid lineages, is associated with three different translocations with a breakpoint in region p11-12 of chromosome 8: t(6;8)(q27;p11), t(8;9)(p11;q33), and t(8;13)(p12;q12), respectively. Using fluorescence in situ hybridization (FISH), we have analysed blood cells from a series of five patients carrying these different translocations. We have identified cosmids from chromosome region 8p11-12 that span the breakpoint in all the cases. They are specific for the FCFR1 gene that encodes a receptor for members of the FGF family. The breakpoint was further detected by Southern and pulsed-field gel electrophoresis analyses with probes from the FGFR1 locus.

Adult↗
PubMed1998

Desmoplastic small round cell tumor: RT-PCR analysis and immunohistochemical detection of the Wilm's tumor gene WT1.

Desmoplastic small round cell tumor is an aggressive neoplasm first described in 1991. Recently, a reciprocal translocation t(11;22)(p13;q12) has been characterized by conventional cytogenetic studies and molecular analysis. This translocation involves the Ewing's sarcoma gene on chromosome 22 and the Wilms' tumor gene WT1 on chromosome 11. The chimeric transcript corresponding to the fusion gene could be detected by the reverse transcriptase-polymerase chain reaction (RT-PCR). Using an anti-WT1 antibody, the WT1 part of the putative chimeric protein could be recognized by immunohistochemistry. We describe two well-characterized cases of intraabdominal desmoplastic small round cell tumor in two male patients aged 14 and 28 with both RT-PCR analysis and immunostaining for WT1. In this report, we insist on the necessity to increase the RT-PCR analysis in DSRCT in order to obtain a precise differential diagnosis. In addition, WT1 immunostaining may serve as a useful diagnostic marker for DSRCT.

Abdominal Neoplasms↗
PubMed1998

Phenotypic, morphologic changes and Ig secretion induced on B-NHL cells in vitro by interferon alpha and all-trans-retinoic acid: possible progression toward a more differentiated state.

Twenty-five B-cell-nonHodgkin's lymphomas (B-NHL): 6 lymphocytic, 2 centrocytic, 13 follicular, centrocytic/centroblastic, 2 lymphoplasmocytoid and 2 centroblastic were tested for their ability to acquire features of mature plasma cells under the effect of interferon alpha (final concentration, 600 UI/ml), all-trans-retinoic-acid (ATRA) (final concentration, 10(-6) mol/l) and the association of both. B-NHL cells were negatively purified (>99%) by an immunomagnetic method, cultured for 7 d with or without interferon and ATRA, then stained with anti-CD19, CD20, surface Ig, DR, CD38 and with anti-CD138 (syndecan-1) antibody-recognizing plasma cells. Ig production was estimated in culture supernatants by an ELISA method and changes in cell morphology were investigated on May-Grunwald-Giemsa-stained cytospin preparations. In all cases interferon and ATRA, alone or in association, were able to induce changes in the immunophenotypic profile, associated or not with morphologic changes and induction of Ig secretion. All changes were greatly variable from one to the other B-NHL sample and no relationship could be found between a particular pattern of change and the histological subtype. Interferon alpha was more potent than ATRA in inducing changes. In favour of a differentiation process, we observed a concomitant decrease of DR expression and increase of CD38 expression in 8 cases with interferon alpha, and in 4 cases with ATRA. Although interferon- or ATRA-treated cells did not display cytologic, functional features and changes of the immunophenotypic profile fully compatible with those of terminally differentiated cells, these results suggest a possible transition toward more differentiated elements, especially with interferon alpha.

Antigens, Surface↗
PubMed1997

Effects of retinoic acid on a new human erythromegakaryocytic cell line AP-217.

We have characterized a new human cell line AP-217, derived from the peripheral blood of a patient with chronic myeloid leukemia in blastic crisis. The analysis of cell surface antigens and ploidy showed that AP-217 was an erythro-megakaryocytic cell line. The effects of inducers of differentiation were studied and focused on retinoic acid (RA). Uninduced AP-217 cells produced a low level of hemoglobin (Hb) that showed a moderate but significant dose-dependent increase after 13 cis-RA induction (four times above the control at 10(-5) M). To outline this effect, AP-217 cells were cloned at limiting dilution. A subclone (clone 2) was isolated which expressed glycophorin A on 12% of cells, and showed a marked sensitivity to RA. After a 4 day induction with increasing concentrations of RA (1-10 x 10(-6) M) Hb production by clone 2 cells was enhanced 12 times over the control at the highest concentration (10(-5) M). No effect of RA on the Hb production of K-562 and HEL was observed. This increased Hb production occurred simultaneously with a growth inhibition in clonogenic cultures (20% reduction) associated with a drastic reduction of the colony size. Moreover, we demonstrated the expression of mRNA for the beta globin gene in clone 2 and AP-217-cells. This is the first report of a positive effect of RA on the erythroid differentiation of a human leukemic cell line.

Adult↗