PubMed Health⌕ Search

Biomedical subjects

P Vandenberghe

Publications and source records attributed to P Vandenberghe.

At least 19 recordsLinked to original sources
PubMed2007

FIP1L1-PDGFRA in chronic eosinophilic leukemia and BCR-ABL1 in chronic myeloid leukemia affect different leukemic cells.

We investigated genetically affected leukemic cells in FIP1L1-PDGFRA+ chronic eosinophilic leukemia (CEL) and in BCR-ABL1+ chronic myeloid leukemia (CML), two myeloproliferative disorders responsive to imatinib. Fluorescence in situ hybridization specific for BCR-ABL1 and for FIP1L1-PDGFRA was combined with cytomorphology or with lineage-restricted monoclonal antibodies and applied in CML and CEL, respectively. In CEL the amount of FIP1L1-PDGFRA+ cells among CD34+ and CD133+ cells, B and T lymphocytes, and megakaryocytes were within normal ranges. Positivity was found in eosinophils, granulo-monocytes and varying percentages of erythrocytes. In vitro assays with imatinib showed reduced survival of peripheral blood mononuclear cells but no reduction in colony-forming unit growth medium (CFU-GM) growth. In CML the BCR-ABL1 fusion gene was detected in CD34+/CD133+ cells, granulo-monocytes, eosinophils, erythrocytes, megakaryocytes and B-lymphocytes. Growth of both peripheral blood mononuclear cells and CFU-GM was inhibited by imatinib. This study provided evidence for marked differences in the leukemic masses which are targeted by imatinib in CEL or CML, as harboring FIP1L1-PDGFRA or BCR-ABL1.

AC133 Antigen↗
PubMed2006

[A man with FIP1L1/PDGFRA-positive chronic eosinophilic leukemia].

A 39-year-old man was referred from Surinam to the Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands, for a right ventricular tumour, hypereosinophilia and mild thrombocytopenia. He appeared to have chronic eosinophilic leukaemia that was positive for the 'FIP1-like-1-platelet-derived growth factor receptor alpha' (FIP1L1-PDGFRA) gene. In addition, he had signs of a right ventricular thrombus that had existed for at least 6 months. The patient was treated with oral anticoagulants and the tyrosine kinase inhibitor imatinib. The latter therapy resulted in normalisation of leukocyte count and differential values. After 3 months of therapy, the FIP1L1-PDGFRA fusion transcript was no longer detectable in peripheral blood. After 1 year of follow up, the patient was in complete haematological and molecular remission for chronic eosinophilic leukaemia. The cardiac mass remained unchanged, but caused no haemodynamic problems.

Adult↗
PubMed2006

Cytogenetics and molecular genetics of T-cell acute lymphoblastic leukemia: from thymocyte to lymphoblast.

For long, T-cell acute lymphoblastic leukemia (T-ALL) remained in the shadow of precursor B-ALL because it was more seldom, and showed a normal karyotype in more than 50% of cases. The last decennia, intense research has been carried out on different fronts. On one side, development of normal thymocyte and its regulation mechanisms have been studied in multiple mouse models and subsequently validated. On the other side, molecular cytogenetics (fluorescence in situ hybridization) and mutation analysis revealed cytogenetically cryptic aberrations in almost all cases of T-ALL. Also, expression microarray analysis disclosed gene expression signatures that recapitulate specific stages of thymocyte development. Investigations are still very much actual, fed by the discovery of new genetic aberrations. In this review, we present a summary of the current cytogenetic changes associated with T-ALL. The genes deregulated by translocations or mutations appear to encode proteins that are also implicated in T-cell development, which prompted us to review the 'normal' and 'leukemogenic' functions of these transcription regulators. To conclude, we show that the paradigm of multistep leukemogenesis is very much applicable to T-ALL and that the different genetic insults collaborate to maintain self-renewal capacity, and induce proliferation and differentiation arrest of T-lymphoblasts. They also open perspectives for targeted therapies.

Cell Lineage↗
PubMed2006

Coexistence of light chain disease and chronic lymphocytic leukaemia, a complex karyotype with a rapid fatal outcome.

We report on a 48-year-old man with concomitantly diagnosed kappa expressing chronic lymphocytic leukaemia (CLL) and lambda light chain disease with highly complex chromosomal aberrations. The clinical course of the disease was very aggressive with survival of only 1 month. We demonstrate the distinct clonal origin by cytogenetic data and immunoglobulin rearrangement studies. To our knowledge this is the first report of a light chain disease associated with CLL.

Chromosomes, Human, Pair 13↗
PubMed2006

CTLA-4 interacts with STAT5 and inhibits STAT5-mediated transcription.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4; CD152) is a member of the immunoglobulin gene superfamily with strong homology to the receptor CD28 with which it shares the ligands CD80 and CD86. Unlike CD28, a potent costimulator of T-cell responses, CTLA-4 is transiently expressed on the cell surface of activated T cells and appears to operate predominantly as a negative regulator of T-cell proliferation. Signal transduction mechanisms utilized by CTLA-4 remain unclear although several mechanisms have been implicated. In this study, we show that the cytoplasmic domain of CTLA-4, but not of CD28, binds to STAT5 in yeast two-hybrid assay and in coimmunoprecipitation assays. Mutations of Tyr165 and Tyr182 in CTLA-4 did not abrogate the interaction of STAT5 with CTLA-4. Finally, the overexpression of CTLA-4 in Jurkat T cells inhibits STAT-mediated activation of STAT5 responsive elements. These results suggest that CTLA-4 and STAT5 interact in T cells and that this interaction is important for CTLA-4 signalling.

Antigens, CD↗
PubMed2005

CD34+ marrow progenitors from MDS patients with high levels of intramedullary apoptosis have reduced expression of alpha4beta1 and alpha5beta1 integrins.

Excessive intramedullary apoptosis is central in the pathogenesis of myelodysplastic syndromes (MDS). Growth-inhibiting cytokines, the Fas/FasLigand pathway, and autoreactive cytotoxic T-lymphocytes have been identified to be important proapoptotic factors in MDS. In normal hematopoiesis, alpha4beta1 and alpha5beta1 integrin-mediated interactions between progenitors and fibronectin are critical for progenitor cell survival. In this study, we have used flow cytometry to quantify the expression levels of members of the beta1 integrin family on CD34(+) marrow progenitors in 27 untreated patients with MDS, three with s-AML, and 25 control subjects. In MDS, we observed that nonapoptotic progenitors significantly downregulate cell surface expression levels of alpha4 and beta1 integrin chains compared with healthy controls. Downregulation of alpha4, beta1, and also alpha5 was present in MDS patients with > or =25% apoptotic progenitors, irrespective of their French, American, British subcategory. Reduced cell surface expression levels of alpha4, alpha5, and beta1 did also correlate with decreased in vitro adhesiveness to fibronectin fragments. Therefore, our observations suggest that downregulation of alpha4beta1 and alpha5beta1 integrins on CD34(+) progenitors could be a newly identified proapoptotic mechanism in MDS.

Aged↗
PubMed2005

A new recurrent inversion, inv(7)(p15q34), leads to transcriptional activation of HOXA10 and HOXA11 in a subset of T-cell acute lymphoblastic leukemias.

Chromosomal translocations with breakpoints in T-cell receptor (TCR) genes are recurrent in T-cell malignancies. These translocations involve the TCRalphadelta gene (14q11), the TCRbeta gene (7q34) and to a lesser extent the TCRgamma gene at chromosomal band 7p14 and juxtapose T-cell oncogenes next to TCR regulatory sequences leading to deregulated expression of those oncogenes. Here, we describe a new recurrent chromosomal inversion of chromosome 7, inv(7)(p15q34), in a subset of patients with T-cell acute lymphoblastic leukemia characterized by CD2 negative and CD4 positive, CD8 negative blasts. This rearrangement juxtaposes the distal part of the HOXA gene cluster on 7p15 to the TCRbeta locus on 7q34. Real time quantitative PCR analysis for all HOXA genes revealed high levels of HOXA10 and HOXA11 expression in all inv(7) positive cases. This is the first report of a recurrent chromosome rearrangement targeting the HOXA gene cluster in T-cell malignancies resulting in deregulated HOXA gene expression (particularly HOXA10 and HOXA11) and is in keeping with a previous report suggesting HOXA deregulation in MLL-rearranged T- and B cell lymphoblastic leukemia as the key factor in leukaemic transformation. Finally, our observation also supports the previous suggested role of HOXA10 and HOXA11 in normal thymocyte development.

Adolescent↗
PubMed2005

FOXP1, a gene highly expressed in a subset of diffuse large B-cell lymphoma, is recurrently targeted by genomic aberrations.

The transcription factor Forkhead box protein P1 (FOXP1) is highly expressed in a proportion of diffuse large B-cell lymphoma (DLBCL). In this report, we provide cytogenetic and fluorescence in situ hybridization (FISH) data showing that FOXP1 (3p13) is recurrently targeted by chromosome translocations. The genomic rearrangement of FOXP1 was identified by FISH in three cases with a t(3;14)(p13;q32) involving the immunoglobulin heavy chain (IGH) locus, and in one case with a variant t(2;3) affecting sequences at 2q36. These aberrations were associated with strong expression of FOXP1 protein in tumor cells, as demonstrated by immunohistochemistry (IHC). The cases with t(3p13) were diagnosed as DLBCL ( x 1), gastric MALT lymphoma ( x 1) and B-cell non-Hodgkin's lymphoma, not otherwise specified ( x 2). Further IHC and FISH studies performed on 98 cases of DLBCL and 93 cases of extranodal marginal zone lymphoma showed a high expression of FOXP1 in approximately 13 and 12% of cases, respectively. None of these cases showed, however, FOXP1 rearrangements by FISH. However, over-representation of the FOXP1 locus found in one additional case of DLBCL may represent another potential mechanism underlying an increased expression of this gene.

Aged↗
PubMed2005

Real-time reverse transcription-PCR and fluorescence in-situ hybridization are complementary to understand the mechanisms involved in HER-2/neu overexpression in human breast carcinomas.

AIMS: To evaluate the HER-2/neu status at the mRNA and DNA level of breast carcinomas and to compare it with HER-2/neu receptor overexpression by immunohistochemistry (IHC). METHODS AND RESULTS: In 32 invasive breast carcinomas, frozen tissue was available for real-time detection of HER-2/neu mRNA levels by reverse transcription-polymerase chain reaction (RT-PCR). Corresponding paraffin sections were examined by IHC and fluorescence in-situ hybridization (FISH). Thereby, different IHC and FISH procedures were compared. Using microwave epitope retrieval, all 32 cases scored 3+ on IHC, whereas only 28 out of 32 cases scored IHC 3+ using water bath epitope retrieval. All of these 28 cases showed increased levels of HER-2/neu mRNA. Dual-colour FISH analysis showed corresponding gene amplification in all 28 cases, with two cases showing a peculiar amplification pattern. In the remaining four cases, scoring IHC 2+ using water bath epitope retrieval, mRNA levels were not elevated. Three cases did not have gene amplification and one case showed low-level HER-2/neu gene amplification. All four carcinomas showed chromosome 17 polysomy. CONCLUSIONS: Real-time RT-PCR is accurate in selecting breast carcinoma cases scoring 3+ by IHC with high-level gene amplification. Results obtained by dual-colour FISH suggest that mechanisms leading to HER-2/neu receptor overexpression may be different between carcinomas scoring 2+ and 3+ on IHC, with polysomy 17 found in the former and gene amplification in the latter.

Breast Neoplasms↗
PubMed2004

Fusion of NUP214 to ABL1 on amplified episomes in T-cell acute lymphoblastic leukemia.

In T-cell acute lymphoblastic leukemia (T-ALL), transcription factors are known to be deregulated by chromosomal translocations, but mutations in protein tyrosine kinases have only rarely been identified. Here we describe the extrachromosomal (episomal) amplification of ABL1 in 5 of 90 (5.6%) individuals with T-ALL, an aberration that is not detectable by conventional cytogenetics. Molecular analyses delineated the amplicon as a 500-kb region from chromosome band 9q34, containing the oncogenes ABL1 and NUP214 (refs. 5,6). We identified a previously undescribed mechanism for activation of tyrosine kinases in cancer: the formation of episomes resulting in a fusion between NUP214 and ABL1. We detected the NUP214-ABL1 transcript in five individuals with the ABL1 amplification, in 5 of 85 (5.8%) additional individuals with T-ALL and in 3 of 22 T-ALL cell lines. The constitutively phosphorylated tyrosine kinase NUP214-ABL1 is sensitive to the tyrosine kinase inhibitor imatinib. The recurrent cryptic NUP214-ABL1 rearrangement is associated with increased HOX expression and deletion of CDKN2A, consistent with a multistep pathogenesis of T-ALL. NUP214-ABL1 expression defines a new subgroup of individuals with T-ALL who could benefit from treatment with imatinib.

Amino Acid Sequence↗
PubMed2004

Clinical and molecular features of FIP1L1-PDFGRA (+) chronic eosinophilic leukemias.

Detection of the FIP1L1-PDGFRA fusion gene or the corresponding cryptic 4q12 deletion supports the diagnosis of chronic eosinophilic leukemia (CEL) in patients with chronic hypereosinophilia. We retrospectively characterized 17 patients fulfilling WHO criteria for idiopathic hypereosinophilic syndrome (IHES) or CEL, using nested RT-PCR and interphase fluorescence in situ hybridization (FISH). Eight had FIP1L1-PDGFRA (+) CEL, three had FIP1L1-PDGFRA (-) CEL and six had IHES. FIP1L1-PDGFRA (+) CEL responded poorly to steroids, hydroxyurea or interferon-alpha, and had a high probability of eosinophilic endomyocarditis (n=4) and disease-related death (n=4). In FIP1L1-PDGFRA (+) CEL, palpable splenomegaly was present in 5/8 cases, serum vitamin B(12) was always markedly increased, and marrow biopsies revealed a distinctively myeloproliferative aspect. Imatinib induced rapid complete hematological responses in 4/4 treated FIP1L1-PDGFRA (+) cases, including one female, and complete molecular remission in 2/3 evaluable cases. In the female patient, 1 log reduction of FIP1L1-PDGFRA copy number was reached as by real-time quantitative PCR (RQ-PCR). Thus, correlating IHES/CEL genotype with phenotype, FIP1L1-PDGFRA (+) CEL emerges as a homogeneous clinicobiological entity, where imatinib can induce molecular remission. While RT-PCR and interphase FISH are equally valid diagnostic tools, the role of marrow biopsy in diagnosis and of RQ-PCR in disease and therapy monitoring needs further evaluation.

Adult↗
PubMed2004

Circulating myeloid and lymphoid precursor dendritic cells are clonally involved in myelodysplastic syndromes.

Circulating myeloid and lymphoid precursor dendritic cell (pDC) counts were determined in peripheral blood from 22 patients with myelodysplastic syndromes (MDS) by a single-platform flow cytometric protocol. The absolute count of myeloid and lymphoid pDC, as well as their relative number (as proportion of mononuclear cells or total leukocytes) was significantly lower in MDS (n=22) than in healthy controls (n=41). In 11 patients with chromosomal aberrations, purified pDC were examined by interphase fluorescence in situ hybridization. This revealed clonal involvement of myeloid as well as lymphoid pDC in all of them. These data therefore strongly suggest that myeloid and lymphoid pDC share a common precursor. Whether reduced peripheral blood counts of pDC contribute to the immunological abnormalities observed in MDS remains to be investigated.

Adult↗
PubMed2002

[A man with plasma cell dyscrasia and polyneuropathy due to POEMS syndrome].

In a 52-year-old man with general malaise, muscle stiffness and weakness, POEMS-syndrome was diagnosed based on polyneuropathy, splenomegaly, lymphadenopathy, subclinical hypothyroidism and the presence of a monoclonal paraprotein with osteosclerotic lesions and an indurated skin (POEMS is an acronym for Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, Skin changes). This is a rare systemic disease from the clinical spectrum of plasma cell dyscrasias with polyneuropathy. The clinical picture is broader and more pleomorphic than the acronym suggests. The possibility of a POEMS syndrome should be considered in the differential diagnosis of polyneuropathy in association with monoclonal gammopathy. Quite often it is associated with osteosclerotic myeloma or mixed osteoscleroticlytic lesions. The patient described was treated with high dose corticosteroids which were gradually decreased over the next three months, upon which a marked improvement could be seen. The general malaise subsided, as did the splenomegaly, and the skin became supple again.

Adrenal Cortex Hormones↗