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H Avet-Loiseau

Publications and source records attributed to H Avet-Loiseau.

At least 37 records · Page 2Linked to original sources
PubMed2000

Deletion of 5q31 is observed in megakaryocytic cells in patients with myelodysplastic syndromes and a del(5q), including the 5q- syndrome.

One of the most common structural rearrangements in myelodysplastic syndrome (MDS) is a deletion of the long arm of chromosome 5, del(5q). The 5q- syndrome is a distinct entity, that presents with specific morphologic abnormalities of the megakaryocytic lineage. Thus, we evaluated the presence or absence of the del(5q) in these cells. We performed fluorescence in situ hybridization analysis using unique sequence probes (one for 5q31, the other for the 5p telomeric band), and tested bone marrow specimens from 10 patients with MDS (including 6 patients with the 5q- syndrome) and a del(5q). Megakaryocytes were identified by nuclear morphology, size, and ploidy index. Our results demonstrate the presence of the del(5q) in the megakaryocytic lineage and, thus, the involvement of these cells in the disease process.

Age Factors↗
PubMed2000

Reactive plasmacytoses in multiple myeloma during hematopoietic recovery with G- or GM-CSF.

We report on three cases of reactive plasmacytoses (RP) in the course of multiple myeloma (MM). The three patients achieved complete remission following high dose melphalan and peripheral blood stem cell transplantation. These transient plasmacytoses had all the characteristics of RP, i.e. expansion of highly proliferative polyclonal plasma cells (PC) with a normal phenotype and genotype and corresponding to expansion of both PC progenitors (plasmablasts) and PC precursors (early plasma cells). These cells were easily distinguished from malignant PC of the corresponding patients evaluated at diagnosis, especially by their phenotypic and genotypic features.

Female↗
PubMed2000

Cyclin D1 expression in patients with multiple myeloma.

INTRODUCTION: Chromosomal abnormalities are detected in 50 to 70% of patients with multiple myeloma (MM). By conventional cytogenetic analysis, a t(11;14)(q13;q32) is observed at a frequency of 3 to 14%. MATERIALS AND METHODS: To demonstrate a cyclin D1 expression in MM patients or MM cell lines, 14 patients with multiple myeloma (MM) and nine human multiple myeloma cell lines (HMCL) were screened by a competitive RT-PCR and/or Northern blot analysis for cyclin D1 expression. Furthermore, we screened 10 MM patients with FISH to demonstrate a relationship between the cyclin D1 expression and the presence of the t(11;14). RESULTS: Five HMCL had a cyclin D1 overexpression: three of them had a t(11;14)(q13;q32) and two had extra copies of chromosome 11. A cyclin D1 expression was found at diagnosis in seven out of 14 untreated MM patients (50%). Out of 14 MM patients, FISH studies were performed in 10 patients. A t(11;14) was detected in three out of 10 patients and extra copies of chromosome 11 were found in two additional patients. CONCLUSION: Cyclin D1 expression is a common event in MM patients (50%) and is associated either with a t(11;14)(q13;q32) or extra copies of chromosome 11. The prognostic role of the cyclin D1 expression and the level of this expression, as compared to other B-cell chronic lymphoproliferative disorders such as mantle cell lymphoma or hairy cell leukemia, remains to be determined in the pathogenesis of multiple myeloma.

Bone Marrow↗
PubMed2000

IgG-secreting lymphoplasmacytoid leukaemia: a B-cell disorder with extensively mutated VH genes undergoing Ig isotype-switching frequently associated with trisomy 12.

We investigated 16 patients with elevated serum monoclonal IgG and a leukaemic B-cell lymphocytic disorder different from multiple myeloma. Their clinical history was that of a non-aggressive disease with dominant splenomegaly and long survival. Whereas abnormal blood and bone marrow cells were predominantly small lymphocytes with a few lymphoplasmacytoid cells, histopathological features included a lymphoplasmacytic infiltrate in eight cases. Most frequently, abnormal blood cells displayed a CD19+CD5-CD23+/- immunophenotype different from that of chronic lymphocytic leukaemia, except in two cases with a CD19+CD5+CD23+ phenotype. Interestingly, a coexistent serum monoclonal IgM and/or surface IgMG+ with identical light chain was identified in 10 patients, whereas in the remaining six patients only IgG expression was determined. VH gene analysis was performed in eight patients to investigate the clonal origins of tumour cells. All cases utilized the VH3 family, with evidence of extensive somatic mutations and intraclonal homogeneity in all cases. VH gene analysis indicated a clonal relationship between cells expressing IgM and IgG, with one case being biclonal. Cytogenetic evaluation showed a high incidence of trisomy 12 (60%) and 13q14 deletion (40%). In conclusion, we have described an unusual subset of low-grade lymphoma with high-serum IgG and frequent lymphoplasmacytoid features in which tumour cells derive from post-follicular memory B cells undergoing isotype switching with some cases arrested at both the IgM and IgG stage and others as IgG-positive cells only.

Adult↗
PubMed2000

Fluorescence in situ hybridization on peripheral-blood specimens is a reliable method to evaluate cytogenetic response in chronic myeloid leukemia.

PURPOSE: To evaluate the usefulness of fluorescence in situ hybridization (FISH) on peripheral-blood specimens to evaluate the cytogenetic response to treatment in patients with chronic myeloid leukemia (CML). PATIENTS AND METHODS: In a first attempt, we analyzed 62 bone marrow specimens using interphase FISH and compared the results with those of conventional cytogenetics. In a second step, we analyzed 60 paired sets of bone marrow and peripheral-blood specimens with interphase FISH. RESULTS: The results of interphase FISH agreed with conventional cytogenetics on bone marrow for most patients, and only minor differences were found (r =.98). The comparison of interphase FISH on bone marrow versus peripheral-blood specimens showed a strong correlation between these two specimen sources (r =.97). CONCLUSION: Our results confirmed that FISH is a sensitive technique for the evaluation of response to treatment in patients with CML. Moreover, our study suggests that follow-up of cytogenetic response to therapy can be evaluated on peripheral-blood specimens, thus enabling an easier and more frequent evaluation of patients. The next step will be to evaluate this technique in a large prospective trial to define the prognostic value of complete remissions evaluated by FISH.

Blood Cells↗
PubMed1999

Genetic alterations in early-onset invasive breast carcinomas: correlation of c-erbB-2 amplification detected by fluorescence in situ hybridization with p53 accumulation and tumor phenotype.

p53 tumor-suppressor gene mutation and p53 protein over-expression have been reported with higher frequency in early-onset breast carcinomas (EOBC). Given the role attributed to normal p53 protein in DNA-repair mechanisms, other somatic genomic alterations would be expected to be associated with this abnormality. Amplification of the c-erbB-2 (HER-2/neu) oncogene and over-expression of the corresponding p185erbB-2 protein have been linked to prognosis and response to therapy in breast cancer. In a retrospective study of 62 formalin-fixed paraffin-embedded invasive EOBC (diagnosed at 35 years or less), the amplification status of the c-erbB-2 gene detected by fluorescence in situ hybridization (FISH) using a unique sequence probe was compared with p53 protein accumulation measured by immunohistochemistry (IHC) and phenotypic features. p185erbB2-protein expression was also detected by immunohistochemistry, together with estrogen-receptor (ER) and progesterone-receptor (PR) expression. The data for a sub-set of 33 node-negative EOBC cases were compared with 70 node-negative tumors diagnosed in women above 36 years of age. Compared with node-negative BC in older women, node-negative EOBC was significantly more likely to feature high grade, high proliferation rate, negative ER and/or PR and p53 over-expression (p < 0.05). A trend toward a higher incidence of c-erbB-2 amplification in EOBC (21% vs. 9%) reached near-significance (p = 0.07). In EOBC, c-erbB-2 amplification and p53 over-expression were not associated with high tumor grade or high cell-proliferation rate, in contrast to the significant associations of these markers in tumors in older women. Abnormalities in tumor markers, including c-erbB-2 gene amplification and p53-protein over-expression, occur at different rates in women with EOBC as compared with BC developing in older women. This finding may reflect a different pathogenesis for EOBC, and warrants further investigation.

Adult↗
PubMed1999

Monosomy 13 is associated with the transition of monoclonal gammopathy of undetermined significance to multiple myeloma. Intergroupe Francophone du Myélome.

Chromosomal abnormalities are present in most (if not all) patients with multiple myeloma (MM) and primary plasma cell leukemia (PCL). Furthermore, recent data have shown that numerical chromosomal changes are present in most individuals with monoclonal gammopathy of undetermined significance (MGUS). Epidemiological studies have shown that up to one third of MM may emerge from pre-existing MGUS. To clarify further possible stepwise chromosomal aberrations on a pathway between MGUS and MM, we have analyzed 158 patients with either MM or primary PCL and 19 individuals with MGUS using fluorescence in situ hybridization (FISH). Our FISH analyses were designed to detect illegitimate IGH rearrangements at 14q32 or monosomy 13. Whereas translocations involving the 14q32 region were observed with a similar incidence (60%) in both conditions, a significant difference was found in the incidence of monosomy 13 in MGUS versus MM or primary PCL. It was present in 40% of MM/PCL patients, but in only 4 of 19 MGUS individuals. Moreover, whereas monosomy 13 was found in the majority of plasma cells in MM, it was observed only in cell subpopulations in MGUS. It is noteworthy that, in a group of 20 patients with MM and a previous MGUS history, incidence of monosomy 13 was 70% versus 31% in MM patients without a known history of MGUS (P =.002). Thus, this study highlights monosomy 13 as correlated with the transformation of MGUS to overt MM and may define 2 groups of MM with possible different natural history and outcome, ie, post-MGUS MM with a very high incidence of monosomy 13 and de novo MM in which other genetic events might be involved. Serial analyses of individuals with MGUS will be needed to validate this model.

Aged↗
PubMed1999

14q32 translocations and monosomy 13 observed in monoclonal gammopathy of undetermined significance delineate a multistep process for the oncogenesis of multiple myeloma. Intergroupe Francophone du Myélome.

Clonal plasma cells in monoclonal gammopathy of undetermined significance (MGUS) have been shown to bear copy number chromosome changes. To extend our knowledge of MGUS to structural chromosomal abnormalities, we have performed fluorescence in situ hybridization experiments with probes directed to the 14q32 and 13q14 chromosomal regions in 100 patients with either MGUS or smoldering multiple myeloma (SMM). 14q32 abnormalities were observed in at least 46% of patients with MGUS/SMM, with these abnormalities being present in the majority of clonal plasma cells. Whereas t(11;14)(q13;q32) occurs in 15% of MGUS/SMM patients, an incidence similar to that of overt multiple myeloma (MM) patients, translocation t(4;14)(p16;q32) is observed in only 2% of these cases [P = 0.002 for difference with t(11;14)], as compared with 12% in MM patients (P = 0.013). Monoallelic deletions of the 13q14 region were found in 21% of patients, with two types of situations. In half of the evaluable patients, and especially in patients with SMM, the deletion is present in the majority of clonal plasma cells, as in MM, whereas in the other half of the evaluable patients (essentially in MGUS patients), it is observed in subclones only. These data enable us to elaborate a plasma cell oncogenesis model from MGUS to MM.

Chromosome Mapping↗
PubMed1999

High incidence of cryptic translocations involving the Ig heavy chain gene in multiple myeloma, as shown by fluorescence in situ hybridization.

Cytogenetic studies have shown rearrangements of the Ig heavy chain (IGH) gene at 14q32 in 10-60% of patients with multiple myeloma (MM) or primary plasma cell leukemia (PCL). Analysis of MM patients and human myeloma cell lines (HMCL) using interphase fluorescence in situ hybridization (FISH) and molecular techniques has shown IGH rearrangements in 75% of MM cases and in up to 100% of HMCL. A review of the literature revealed at least 18 different partner chromosomal regions. To investigate whether some of these translocations were recurrent and possibly to identify new partner regions, we developed a set of FISH probes to detect every IGH recombination. We analyzed 28 MM and 4 primary PCL patients with abnormal karyotypes and 12 HMCL. Whereas conventional cytogenetics detected a 14q32 abnormality in only 15% of the patients, FISH detected it in 47% of patients and in 75% of HMCL. The partner chromosome was identified in 10 of 15 patients with a 14q32 rearrangement. Interestingly, the same t(4; 14)(p16;q32) was detected in five patients and three HMCL, i.e., 33% of patients and HMCL with an IGH rearrangement. New partner chromosomal regions have also been identified, i.e., 9p13, 12p11, 12p13, and Xq28, besides the previously reported 8q24, 11q13, 12q24, and 16q24 rearrangements. The genes involved in these new translocations are not known, except for 9p13, where PAX5 was shown to be the partner gene. We conclude that: I) IGH recombinations are frequent but not constant in MM, 2) these rearrangements often occur through cryptic translocations, and 3) the t(4;14)(p16;q32) is one of the most frequent translocations, but many other chromosomal regions may be involved.

Chromosomes, Human, Pair 14↗
PubMed1999

Detection of translocation t(11;14)(q13;q32) in mantle cell lymphoma by fluorescence in situ hybridization.

To assess an unequivocal diagnosis of mantle cell lymphoma (MCL), we have developed a fluorescence in situ hybridization (FISH) assay, enabling the demonstration of t(11;14)(q13;q32) directly on pathological samples. We have first selected CCND1 and IGH probes encompassing the breakpoint regions on both chromosomes. Then, we have defined experimental conditions enabling us to obtain bright clear-cut signals in all of the samples, independently of the initial fixation conditions. We have analyzed single-cell suspensions from 26 formalin-fixed, paraffin-embedded MCL samples with this set of probes. In all cases, we have found a fusion signal (ie, a t(11;14)(q13;q32) translocation) in 14% to 99% of cells (median, 87%). So far, IGH-CCND1 fusions have been detected in all of the 51 MCL patients that we have analyzed by FISH (either on paraffin-embedded tumor samples or on peripheral blood samples). Regarding the low sensitivity of other techniques used to diagnose t(11;14)(q13;q32) (ie, 70% to 75% for cytogenetics and 50% to 60% for polymerase chain reaction), our FISH assay is by far the most sensitive technique. Moreover, because of the quality of the fluorescent signals and the rapidity of the experiment, this technique is widely applicable, even in routine cytogenetics or pathology laboratories. As MCL patients are usually refractory to standard therapy, an unambiguous diagnosis is needed to propose adapted therapeutic strategies, and this highly sensitive assay may be of great value for accurate diagnosis in difficult cases.

Adult↗
PubMed1999

Comparative genomic hybridization detects many recurrent imbalances in central nervous system primitive neuroectodermal tumours in children.

A series of 23 children with primitive neuroectodermal tumours (PNET) were analysed with comparative genomic hybridization (CGH). Multiple chromosomal imbalances have been detected in 20 patients. The most frequently involved chromosome was chromosome 17, with a gain of 17q (11 cases) and loss of 17p (eight cases). Further recurrent copy number changes were detected. Extra copies of chromosome 7 were present in nine patients and gains of 1q were detected in six patients. A moderate genomic amplification was detected in one patient, involving two sites on 3p and the whole 12p. Losses were more frequent, and especially involved the chromosomes 11 (nine cases), 10q (eight cases), 8 (six cases), X (six patients) and 3 (five cases), and part of chromosome 9 (five cases). These recurrent chromosomal changes may highlight locations of novel genes with an important role in the development and/or progression of PNET.

Adolescent↗
PubMed1999

P53 deletion is not a frequent event in multiple myeloma.

Recently a high incidence of interstitial deletion of the P53 locus has been reported in multiple myeloma (MM) patients. Considering the importance of such an event, we analysed 79 patients with advanced-stage disease using fluorescence in situ hybridization (FISH). Strikingly, we found only 7/79 patients with a P53 deletion. In order to rule out any differences in probe selection, we reanalysed all the patients with the same probe as that used in a previous study, and confirmed the low incidence of P53 deletion (7/79, 9%). The only explanation is a difference in hybridization efficiency. Since hybridization is far less efficient on malignant plasma cells than on other bone marrow cells we suggest that this poor hybridization efficiency may lead to a false P53 deletion.

Gene Deletion↗
PubMed1999

Fish analysis at diagnosis in acute lymphoblastic leukemia.

Many recurrent cytogenetic abnormalities have been described in acute lymphoblastic leukemia (ALL). With improvement of survival, it became evident that some of these chromosomal changes had a major prognostic value: hyperdiploidy and t(12;21) are associated with very long disease free survival, whereas t(9;22) and 11q23 rearrangements correlate with a poor outcome. Because of this prognostic impact, detection of these four specific abnormalities has to be accurate and rapid at diagnosis. In order to reliably analyze ALL patients, we used fluorescence in situ hybridization (FISH). We selected specific probes enabling the detection of the structural rearrangements [t(9;22), t(12;21) and 11q23 rearrangements] directly on interphase cells. Detection of hyperdiploidy was performed using comparative genomic hybridization (CGH). This technique enables to characterize chromosomal gains and losses without requiring metaphase obtention. We showed that this FISH-based approach was complementary to conventional cytogenetics, and should be systematically used in ALL at diagnosis.

Chromosomes, Human, Pair 11↗
PubMed1999

Finding new human minisatellite sequences in the vicinity of long CA-rich sequences.

Microsatellites and minisatellites are two classes of tandem repeat sequences differing in their size, mutation processes, and chromosomal distribution. The boundary between the two classes is not defined. We have developed a convenient, hybridization-based human library screening procedure able to detect long CA-rich sequences. Analysis of cosmid clones derived from a chromosome 1 library show that cross-hybridizing sequences tested are imperfect CA-rich sequences, some of them showing a minisatellite organization. All but one of the 13 positive chromosome 1 clones studied are localized in chromosomal bands to which minisatellites have previously been assigned, such as the 1pter cluster. To test the applicability of the procedure to minisatellite detection on a larger scale, we then used a large-insert whole-genome PAC library. Altogether, 22 new minisatellites have been identified in positive PAC and cosmid clones and 20 of them are telomeric. Among the 42 positive PAC clones localized within the human genome by FISH and/or linkage analysis, 25 (60%) are assigned to a terminal band of the karyotype, 4 (9%) are juxtacentromeric, and 13 (31%) are interstitial. The localization of at least two of the interstitial PAC clones corresponds to previously characterized minisatellite-containing regions and/or ancestrally telomeric bands, in agreement with this minisatellite-like distribution. The data obtained are in close agreement with the parallel investigation of human genome sequence data and suggest that long human (CA)s are imperfect CA repeats belonging to the minisatellite class of sequences. This approach provides a new tool to efficiently target genomic clones originating from subtelomeric domains, from which minisatellite sequences can readily be obtained. [The sequence data described in this paper have been submitted to the EMBL data library under accession nos. AJ000377-AJ000383.]

Bacteriophage P1↗
PubMed1999

Amplification of the 11q23 region in acute myeloid leukemia.

Cytogenetic abnormalities involving the 11q23 region are found in both acute lymphoblastic leukemia (ALL) and myeloid leukemia (AML). Molecular consequences of 11q23 translocations are the formation of chimeric genes, all of them involving the MLL (mixed-lineage leukemia) gene. To evaluate the usefulness of fluorescence in situ hybridization (FISH) in detecting MLL rearrangements in AML, we analyzed 181 patients with an MLL-specific probe. Among them, we detected three patients with multiple FISH signals, reflecting genomic amplification of this chromosomal region. Extra copies of MLL have been reported previously in four patients, but did not correspond to a true gene amplification. For the first time, we describe genomic amplification of the 11q23 region (up to more than 50 copies) in AML patients. This genomic amplification could affect MLL, but other genes in the vicinity could also be the primary target. Genes Chromosomes Cancer 26:166-170, 1999.

Aged↗