Guntram Buesche
Research interests
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InterestsHistopathology, Surgical Pathology, Molecular Pathology, Immunohistochemistry, Cytology, Histopathological techniques, Cytopathology, Anatomical Pathological Conditions, Cytological Techniques, Clinical Pathology, Pathology Hematology
Publications
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8.30Impact points
Long-term transfusion independence in del(5q) MDS patients who discontinue lenalidomide.
Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 09/2011;
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2.03Impact points
Quality assessment of HER2 testing by monitoring of positivity rates.
Virchows Archiv : an international journal of pathology. 08/2011; 459(3):283-9.
Interlaboratory variation in human epidermal growth factor receptor 2 (HER2) testing provides a challenge for targeted therapy in breast and gastric cancer. Assessment of positivity rates among laboratories could help monitor their performance and define reference values for positivity rates to be e... [more] Interlaboratory variation in human epidermal growth factor receptor 2 (HER2) testing provides a challenge for targeted therapy in breast and gastric cancer. Assessment of positivity rates among laboratories could help monitor their performance and define reference values for positivity rates to be expected in a geographic region. Pathologists regularly determined the number of HER2-positive cases (HER2 3+, HER2 2+/amplified or amplified) in their laboratory, and figures were continuously entered into a central website. The overall positivity rate of each participant was calculated and compared with the average rates of all other institutes (n = 42). A total of 18,081 test results on breast cancer and 982 on gastric cancer were entered into the system. Positivity rates for HER2 in breast cancer ranged from 7.6% to 31.6%. Statistically, the results from six institutions qualified as outliers (p < 0.000005). From the remaining institutions encompassing 10,916 assessments, the mean proportion of positive cases was 16.7 ± 3.2% (99% confidence interval 16.6-16.8). The results from six institutions were in between the 95% and 99.5% confidence intervals. For gastric cancer, there was one outlier and the mean positivity rate was 23.2 ± 5.7%. The proportion of HER2-positive breast cancer cases is considerably lower than could have been expected from published studies. By assessing the positivity rates and comparing them with that of all breast or gastric cancers in a given population, pathologists will be alerted to a potential systematic error in their laboratory assay, causative for over- or underestimation of cancer cases suited for anti-HER2 therapy.
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8.30Impact points
Telomere shortening, clonal evolution and disease progression in myelodysplastic syndrome patients with 5q deletion treated with lenalidomide.
Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 07/2011; 26(2):356-8.
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8.30Impact points
Systemic mastocytosis (SM) with associated BCR-ABL-positive myelogenous leukaemia (SM-AHNMD): evidence that mast cells do not belong to the leukaemic clone.
Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 03/2011; 25(6):1050-3.
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4.75Impact points
Lentiviral vectors for induction of self-differentiation and conditional ablation of dendritic cells.
Gene therapy. 03/2011; 18(8):750-64.
Development of lentiviral vectors (LVs) in the field of immunotherapy and immune regeneration will strongly rely on biosafety of the gene transfer. We demonstrated previously the feasibility of ex vivo genetic programming of mouse bone marrow precursors with LVs encoding granulocyte macrophage colon... [more] Development of lentiviral vectors (LVs) in the field of immunotherapy and immune regeneration will strongly rely on biosafety of the gene transfer. We demonstrated previously the feasibility of ex vivo genetic programming of mouse bone marrow precursors with LVs encoding granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4), which induced autonomous differentiation of long-lived dendritic cells (DCs), referred to as self-differentiated myeloid-derived antigen-presenting-cells reactive against tumors (SMART-DCs). Here, LV biosafety was enhanced by using a DC-restricted and physiological promoter, the major histocompatibility complex (MHC) II promoter, and including co-expression of the herpes simplex virus-thymidine kinase (sr39HSV-TK) conditional suicide gene. Tricistronic vectors co-expressing sr39HSV-TK, GM-CSF and IL-4 transcriptionally regulated by the MHCII promoter or the ubiquitous cytomegalovirus (CMV) promoter were compared. Despite the different gene transfer effects, such as the kinetics, levels of transgene expression and persistency of integrated vector copies, both vectors induced highly viable SMART-DCs, which persisted for at least 70 days in vivo and could be ablated with the pro-drug Ganciclovir (GCV). SMART-DCs co-expressing the tyrosine-related protein 2 melanoma antigen administered subcutaneously generated antigen-specific, anti-melanoma protective and therapeutic responses in the mouse B16 melanoma model. GCV administration after immunotherapy did not abrogate DC vaccination efficacy. This demonstrates proof-of-principle of genetically programmed DCs that can be ablated pharmacologically.
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2.92Impact points
Expression of myelopoiesis-associated microRNA in bone marrow cells of atypical chronic myeloid leukaemia and chronic myelomonocytic leukaemia.
Annals of hematology. 03/2011; 90(3):307-13.
The microRNA/miR deregulation in BCR-ABL-negative myelodysplastic-myeloproliferative neoplasms (MDS/MPN) is not known. Myelopoiesis-associated miR-10a, miR-17-5p, miR-155, miR-223 and miR-424 were analysed by real-time polymerase chain reaction (PCR) in bone marrow cells of atypical chronic myeloid ... [more] The microRNA/miR deregulation in BCR-ABL-negative myelodysplastic-myeloproliferative neoplasms (MDS/MPN) is not known. Myelopoiesis-associated miR-10a, miR-17-5p, miR-155, miR-223 and miR-424 were analysed by real-time polymerase chain reaction (PCR) in bone marrow cells of atypical chronic myeloid leukaemia (aCML, n = 7) and chronic myelomonocytic leukaemia (CMML, n = 8) and were compared to BCR-ABL-positive chronic myelogenous leukaemia (CML, n = 10) and non-neoplastic haematopoiesis (n = 10). Down-regulation of miR-10a was found in CMML but also in CML (each p < 0.05, versus controls). Overexpression of miR-424 was detected in aCML (p < 0.05, versus CML and controls). Despite different compositions of bone marrow cells, expression of myelopoiesis-associated microRNA shows mainly similar patterns in aCML and its main differential diagnosis CMML and does not allow discrimination of these two MDS/MPN entities. Therefore, the link of deregulated microRNA expression to disease-related phenotype and the underlying molecular mechanism are still unknown.
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6.42Impact points
Cytogenetic follow-up by karyotyping and fluorescence in situ hybridization: implications for monitoring patients with myelodysplastic syndrome and deletion 5q treated with lenalidomide.
Haematologica. 02/2011; 96(2):319-22.
In patients with low and intermediate risk myelodysplastic syndrome and deletion 5q (del(5q)) treated with lenalidomide, monitoring of cytogenetic response is mandatory, since patients without cytogenetic response have a significantly increased risk of progression. Therefore, we have reviewed cytoge... [more] In patients with low and intermediate risk myelodysplastic syndrome and deletion 5q (del(5q)) treated with lenalidomide, monitoring of cytogenetic response is mandatory, since patients without cytogenetic response have a significantly increased risk of progression. Therefore, we have reviewed cytogenetic data of 302 patients. Patients were analyzed by karyotyping and fluorescence in situ hybridization. In 85 patients, del(5q) was only detected by karyotyping. In 8 patients undergoing karyotypic evolution, the del(5q) and additional chromosomal aberrations were only detected by karyotyping. In 3 patients, del(5q) was only detected by fluorescence in situ hybridization, but not by karyotyping due to a low number of metaphases. Karyotyping was significantly more sensitive than fluorescence in situ hybridization in detecting the del(5q) clone. In conclusion, to optimize therapy control of myelodysplastic syndrome patients with del(5q) treated with lenalidomide and to identify cytogenetic non-response or progression as early as possible, fluorescence in situ hybridization alone is inadequate for evaluation. Karyotyping must be performed to optimally evaluate response.
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5.49Impact points
Bone marrow-derived progenitor cells do not contribute to podocyte turnover in the puromycin aminoglycoside and renal ablation models in rats.
The American journal of pathology. 02/2011; 178(2):494-9.
A key event in the progression of glomerular disease is podocyte loss that leads to focal and segmental glomerulosclerosis (FSGS). Because adult podocytes are postmitotic cells, podocyte replacement by bone marrow-derived progenitors could prevent podocytopenia and FSGS. This study uses double immun... [more] A key event in the progression of glomerular disease is podocyte loss that leads to focal and segmental glomerulosclerosis (FSGS). Because adult podocytes are postmitotic cells, podocyte replacement by bone marrow-derived progenitors could prevent podocytopenia and FSGS. This study uses double immunofluorescence for Wilms' tumor-1 and enhanced green fluorescent protein (eGFP) to examine whether an eGFP-positive bone marrow transplant can replace podocytes under normal circumstances and in 3 different rat models of FSGS: puromycin aminoglycoside nephropathy, subtotal nephrectomy, and uninephrectomy. Bone marrow engraftment was successful, with more than 70% eGFP-positive cells and virtually normal histologic findings. No bone marrow transplant-derived podocytes were found in four control rats after transplantation, in nine rats at up to 10 weeks after puromycin aminoglycoside nephropathy induction, in three rats 23 days after subtotal nephrectomy, and in six rats up to 21 days after uninephrectomy. A total of 2200 glomeruli with 14,474 podocytes were evaluated in all groups. Thus, podocyte replacement by bone marrow-derived cells does not contribute to podocyte turnover in rats, even in models of podocyte damage. This is in contrast to previous studies in mice, in which bone marrow-derived podocytes were found. Further studies will address this discrepancy, which could be explained by species differences or by predominant podocyte regeneration from a parietal epithelial cell niche.
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10.56Impact points
Lentiviral gene transfer regenerates hematopoietic stem cells in a mouse model for Mpl-deficient aplastic anemia.
Blood. 02/2011; 117(14):3737-47.
Thpo/Mpl signaling plays an important role in the maintenance of hematopoietic stem cells (HSCs) in addition to its role in megakaryopoiesis. Patients with inactivating mutations in Mpl develop thrombocytopenia and aplastic anemia because of progressive loss of HSCs. Yet, it is unknown whether this ... [more] Thpo/Mpl signaling plays an important role in the maintenance of hematopoietic stem cells (HSCs) in addition to its role in megakaryopoiesis. Patients with inactivating mutations in Mpl develop thrombocytopenia and aplastic anemia because of progressive loss of HSCs. Yet, it is unknown whether this loss of HSCs is an irreversible process. In this study, we used the Mpl knockout (Mpl(-/-)) mouse model and expressed Mpl from newly developed lentiviral vectors specifically in the physiologic Mpl target populations, namely, HSCs and megakaryocytes. After validating lineage-specific expression in vivo using lentiviral eGFP reporter vectors, we performed bone marrow transplantation of transduced Mpl(-/-) bone marrow cells into Mpl(-/-) mice. We show that restoration of Mpl expression from transcriptionally targeted vectors prevents lethal adverse reactions of ectopic Mpl expression, replenishes the HSC pool, restores stem cell properties, and corrects platelet production. In some mice, megakaryocyte counts were atypically high, accompanied by bone neo-formation and marrow fibrosis. Gene-corrected Mpl(-/-) cells had increased long-term repopulating potential, with a marked increase in lineage(-)Sca1(+)cKit(+) cells and early progenitor populations in reconstituted mice. Transcriptome analysis of lineage(-)Sca1(+)cKit(+) cells in Mpl-corrected mice showed functional adjustment of genes involved in HSC self-renewal.
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2.92Impact points
Thrombospondin-1 (TSP-1) in primary myelofibrosis (PMF) - a megakaryocyte-derived biomarker which largely discriminates PMF from essential thrombocythemia.
Annals of hematology. 01/2011; 90(1):33-40.
Primary myelofibrosis (PMF) is a chronic myeloproliferative neoplasm showing aberrant bone marrow remodeling with increased angiogenesis, progressive matrix accumulation, and fibrosis development. Thrombospondins (TSP) are factors sharing pro-fibrotic and anti-angiogenic properties, and have not bee... [more] Primary myelofibrosis (PMF) is a chronic myeloproliferative neoplasm showing aberrant bone marrow remodeling with increased angiogenesis, progressive matrix accumulation, and fibrosis development. Thrombospondins (TSP) are factors sharing pro-fibrotic and anti-angiogenic properties, and have not been addressed in PMF before. We investigated the expression of TSP-1 and TSP-2 in PMF related to the stage of myelofibrosis (n = 51) and in individual follow-up biopsies by real-time PCR, immunohistochemistry, and confocal laser scanning microscopy (CLSM). TSP-1 was significantly overexpressed (p < 0.05) in all stages of PMF when compared to controls. Individual follow-up biopsies showed involvement of TSP-1 during progressive myelofibrosis. TSP-2 was barely detectable but 40% of cases with advanced myelofibrosis showed a strong expression. Megakaryocytes and interstitial proplatelet formations were shown to be the relevant source for TSP-1 in PMF. Stroma cells like endothelial cells and fibroblasts showed no TSP-1 labeling when double-immunofluorescence staining and CLSM were applied. Based on its dual function, TSP-1 in PMF is likely to be a mediator within a pro-fibrotic environment which discriminates from ET cases. On the other hand, TSP-1 is a factor acting (ineffectively) against exaggerated angiogenesis. Both features suggest TSP-1 to be a biomarker for monitoring a PMF-targeted therapy.
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2.36Impact points
Aberrant proplatelet formation in chronic myeloproliferative neoplasms.
Leukemia research. 11/2010; 34(11):1424-9.
Proplatelets represent pseudopodia of megakaryocytes which extend into bone marrow sinuses to release platelets. Proplatelets were visualized by immunohistochemical and confocal microscopy. In trephines from essential thrombocythaemia (ET, n=10), fibrotic (n=10) and pre-fibrotic (n=10) primary myelo... [more] Proplatelets represent pseudopodia of megakaryocytes which extend into bone marrow sinuses to release platelets. Proplatelets were visualized by immunohistochemical and confocal microscopy. In trephines from essential thrombocythaemia (ET, n=10), fibrotic (n=10) and pre-fibrotic (n=10) primary myelofibrosis (PMF) there was a significant increase of proplatelet density compared with normal bone marrow samples (n=10; p<0.001). Manifest fibrosis exhibited the highest density and volume ratio with significant differences to non-fibrotic PMF (p<0.001) and ET (p<0.001). This study demonstrates that besides megakaryocytic proliferation extensive pseudopodial proplatelet formation provides a hallmark of MPN. Fibrosing differ from non-fibrosing MPN by density and size of aberrant proplatelets.
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Standards and impact of hematopathology in myelodysplastic syndromes (MDS).
Oncotarget. 11/2010; 1(7):483-96.
The diagnosis, classification, and prognostication of patients with myelodysplastic syndromes (MDS) are usually based on clinical parameters, analysis of peripheral blood and bone marrow smears, and cytogenetic determinants. However, a thorough histologic and immunohistochemical examination of the b... [more] The diagnosis, classification, and prognostication of patients with myelodysplastic syndromes (MDS) are usually based on clinical parameters, analysis of peripheral blood and bone marrow smears, and cytogenetic determinants. However, a thorough histologic and immunohistochemical examination of the bone marrow is often required for a final diagnosis and exact classification in these patients. Notably, histology and immunohistology may reveal dysplasia in megakaryocytes or other bone marrow lineages and/or the presence of clusters of CD34-positive precursor cells. In other cases, histology may reveal an unrelated or co-existing hematopoietic neoplasm, or may support the conclusion the patient is suffering from acute myeloid leukemia rather than MDS. Moreover, histologic investigations and immunohistology may reveal an increase in tryptase-positive cells, a coexisting systemic mastocytosis, or bone marrow fibrosis, which is of prognostic significance. To discuss diagnostic algorithms, terminologies, parameters, and specific issues in the hematopathologic evaluation of MDS, a Working Conference involving a consortium of US and EU experts, was organized in June 2010. The outcomes of the conference and resulting recommendations provided by the faculty, are reported in this article. These guidelines should assist in the diagnosis, classification, and prognostication in MDS in daily practice as well as in clinical trials.
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2.36Impact points
Aberrant microRNA expression pattern in myelodysplastic bone marrow cells.
Leukemia research. 09/2010; 34(9):1169-74.
The microRNA/miR system might contribute to deregulation of cell homeostasis/disease phenotype. This is the first approach to generate an expression profile of 365 microRNAs in myelodysplastic syndromes (MDS) with normal karyotype (n=12) and distinct cytogenetic aberrations (n=12). In MDS-del(5q), a... [more] The microRNA/miR system might contribute to deregulation of cell homeostasis/disease phenotype. This is the first approach to generate an expression profile of 365 microRNAs in myelodysplastic syndromes (MDS) with normal karyotype (n=12) and distinct cytogenetic aberrations (n=12). In MDS-del(5q), a series of microRNAs not in the 5q-region was increased. MicroRNAs encoded on chromosomes 5, 7 and 8 were not differentially expressed in MDS with del(5q), -7 or +8. Evaluation in a larger cohort could confirm the up-regulation of the miR-1 in MDS. These findings provide evidence that MDS-haematopoiesis is distinct in its microRNA-expression pattern from non-neoplastic cells.
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2.92Impact points
Patients with del(5q) MDS who fail to achieve sustained erythroid or cytogenetic remission after treatment with lenalidomide have an increased risk for clonal evolution and AML progression.
Annals of hematology. 10/2009;
Lenalidomide consistently induces transfusion independence and complete cytogenetic response in patients with myelodysplastic syndromes with 5q deletion. Only limited information on long-term outcome is currently available. We performed a long-term follow-up analysis of 42 patients with low or inter... [more] Lenalidomide consistently induces transfusion independence and complete cytogenetic response in patients with myelodysplastic syndromes with 5q deletion. Only limited information on long-term outcome is currently available. We performed a long-term follow-up analysis of 42 patients with low or intermediate risk myelodysplastic syndromes and 5q deletion treated with lenalidomide. At a median follow-up of 40 months, 58% of the patients achieved an erythroid response and 48% a cytogenetic response. Thirty-six percent of patients progressed into acute myeloid leukaemia. Most of them (87%) acquired chromosome aberrations in addition to the 5q deletion, i.e. underwent clonal evolution during leukaemogenesis. There were no clinical, cytological or cytogenetic markers at study entry that allowed prediction of increased risk of leukaemic transformation. However, erythroid and cytogenetic responders had a significantly decreased risk of progression to acute myeloid leukaemia (p = 0.001 and p = 0.009, respectively) compared to non-responders. Three and 5 years after study entry, the cumulative incidence of acute myeloid leukaemia for patients with a cytogenetic response was 10% and 21%, respectively, and for patients without cytogenetic response, it was 46% and 60%. Patients with del(5q) myelodysplastic syndromes without erythroid or cytogenetic remission after treatment with lenalidomide have a high risk for clonal evolution and acute myeloid leukaemia progression. In refractory, or relapsing, patients, genetic instability and clonal evolution seem to be the driving forces of leukaemic transformation. Regular follow-up investigations of del(5q) myelodysplastic syndrome patients treated with lenalidomide may help to identify patients requiring alternative treatment strategies.
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6.24Impact points
Gene Therapy of Mpl Deficiency: Challenging Balance Between Leukemia and Pancytopenia.
Molecular therapy : the journal of the American Society of Gene Therapy. 10/2009;
Signaling of the thrombopoietin (THPO) receptor MPL is critical for the maintenance of hematopoietic stem cells (HSCs) and megakaryocytic differentiation. Inherited loss-of-function mutations of MPL cause severe thrombocytopenia and aplastic anemia, a syndrome called congenital amegakaryocytic throm... [more] Signaling of the thrombopoietin (THPO) receptor MPL is critical for the maintenance of hematopoietic stem cells (HSCs) and megakaryocytic differentiation. Inherited loss-of-function mutations of MPL cause severe thrombocytopenia and aplastic anemia, a syndrome called congenital amegakaryocytic thrombocytopenia (CAMT). With the aim to assess the toxicity of retroviral expression of Mpl as a basis for further development of a gene therapy for this disorder, we expressed Mpl in a murine bone marrow transplantation (BMT) model. Treated mice developed a profound yet transient elevation of multilineage hematopoiesis, which showed morphologic features of a chronic myeloproliferative disorder (CMPD) with progressive pancytopenia. Ten percent of mice (3/27) developed erythroleukemia, associated with insertional activation of Sfpi1 and Fli1. The majority of transplanted mice developed a progressive pancytopenia with histopathological features of a myelodysplastic syndrome (MDS)-like disorder. To avoid these adverse reactions, improved retroviral vectors were designed that mediate reduced and more physiological Mpl expression. Self-inactivating gamma-retroviral vectors were constructed that expressed Mpl from the phosphoglycerate kinase (PGK) or the murine Mpl promoter. Mice that received BM cells expressing Mpl from the Mpl promoter were free of any previously observed adverse reactions.
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2.36Impact points
Significant inverse correlation of microRNA-150/MYB and microRNA-222/p27 in myelodysplastic syndrome.
Leukemia research. 08/2009;
We investigated whether, in myelodysplastic syndromes (MDS), aberrant expression of miR-150/miR-221/miR-222 and their designated target mRNA molecules MYB, p27 and c-KIT may be involved in insufficient haematopoiesis. In a series of MDS (n=52), an aberrant increase of miR-150 was found only in MDS w... [more] We investigated whether, in myelodysplastic syndromes (MDS), aberrant expression of miR-150/miR-221/miR-222 and their designated target mRNA molecules MYB, p27 and c-KIT may be involved in insufficient haematopoiesis. In a series of MDS (n=52), an aberrant increase of miR-150 was found only in MDS with associated del(5q) (n=9; p<0.01). The mRNA expression of transcription factor MYB, the designated target of miR-150, was shown to correlate inversely with the miR-150 level. Acute leukaemia evolving from MDS (n=11) showed significantly decreased levels of miR-221 but not miR-222. We conclude that inhibition of proliferation via over-expressed miR-150 might contribute to myelodysplastic haematopoiesis in MDS-del(5q).
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3.11Impact points
JAK2(V617F) allele burden discriminates essential thrombocythaemia from a subset of pre-fibrotic stage primary myelofibrosis.
Experimental hematology. 08/2009;
OBJECTIVE: Among Philadelphia chromosome-negative myeloproliferative neoplasms (Ph(-) MPN), essential thrombocythaemia (ET) and the pre-fibrotic phase of primary myelofibrosis (PMF) represent two subtypes with considerable overlap. METHODS: In this study, histopathological classification of 490 MPN ... [more] OBJECTIVE: Among Philadelphia chromosome-negative myeloproliferative neoplasms (Ph(-) MPN), essential thrombocythaemia (ET) and the pre-fibrotic phase of primary myelofibrosis (PMF) represent two subtypes with considerable overlap. METHODS: In this study, histopathological classification of 490 MPN cases was correlated with the allelic burden of JAK2(V617F) and MPL(W515L). RESULTS: Ph(-) MPN entities largely overlap with regard to JAK2(V617F) and MPL(W515L) allele burden but ET displayed mutant allele burden <50%. PMF with different stages of myelofibrosis all yielded similar JAK2(V617F) allele burden which provides evidence that pre-fibrotic stage PMF is different from ET. Whereas at initial presentation a quarter of pre-fibrotic PMF cases exhibited an allele burden exceeding 50% (38% median JAK2(V617F) alleles, n=102), in ET, its main differential diagnosis, not a single case was found with more than 40% JAK2(V617F) alleles (median 24% JAK2(V617F) alleles, n=90, p<0.001). Increase in JAK2(V617F) alleles during follow-up cannot be linked to fibrosis or blastic progression but indicates polycythaemic transformation in ET. MPL(W515L) was found in 3% of ET and 8% of PMF, with a significantly higher percentage of mutated alleles in fibrotic PMF (median 78% MPL(W515L) alleles; p<0.05). CONCLUSION: Histopathological categories ET and pre-fibrotic PMF correlate with significant differences in mutant allelic burden of JAK2(V617F) but not of MPL(W515L) which, by contrast to JAK2(V617F), shows a higher percentage of mutated alleles in fibrotic than in pre-fibrotic cases. Thus, for Ph(-) MPN in which ET and pre-fibrotic PMF represent the most probable diagnoses, a JAK2(V617F) allele burden >50% favours a diagnosis of pre-fibrotic PMF.
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4.60Impact points
Identification of new target molecules PTK2, TGFBR2 and CD9 overexpressed during advanced bone marrow remodelling in primary myelofibrosis.
British journal of haematology. 07/2009;
Summary Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by remodelling of the bone marrow, including progressive myelofibrosis and exaggerated angiogenesis. Advanced PMF frequently shows a full-blown fibre meshwork, which avoids aspiration of cells, and the expression prof... [more] Summary Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by remodelling of the bone marrow, including progressive myelofibrosis and exaggerated angiogenesis. Advanced PMF frequently shows a full-blown fibre meshwork, which avoids aspiration of cells, and the expression profile of genes related to stroma pathology at this stage remains largely undetermined. We investigated bone marrow core biopsies in PMF showing various degrees of myelofibrosis by custom-made low density arrays (LDA) representing target genes with designated roles in synthesis of extracellular matrix, matrix remodelling, cellular adhesion and motility. Among a set of 11 genes up-regulated in advanced stages of PMF (P </= 0.01) three candidates, PTK2 protein tyrosine kinase 2 (PTK2), transforming growth factor beta type II receptor (TGFBR2) and motility-related protein-1 (CD9 molecule, CD9), were investigated in more detail. PTK2, TGFBR2 and CD9 were significantly overexpressed in larger series of advanced PMF stages (P </= 0.01 respectively). Endothelial cells of the increased microvessel network in PMF could be identified as a predominant source for PTK2, TGFBR2 and CD9. CD9 also strongly identified activated fibroblasts in advanced myelofibrosis. We conclude that PTK2, TGFBR2 and CD9 represent new target molecules involved in bone marrow remodelling of PMF and warrant further investigation for potential targeted therapy.
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2.92Impact points
Opposite expression pattern of Src kinase Lyn in acute and chronic haematological malignancies.
Annals of hematology. 03/2009;
Lck/yes-related novel (Lyn) tyrosine kinase overexpression has been suggested to be important for leukaemic cell growth making it an attractive target for therapy. By contrast, Lyn deficiency was shown to be responsible for a phenotype resembling myeloproliferative neoplasm (MPN) in mice. We aimed t... [more] Lck/yes-related novel (Lyn) tyrosine kinase overexpression has been suggested to be important for leukaemic cell growth making it an attractive target for therapy. By contrast, Lyn deficiency was shown to be responsible for a phenotype resembling myeloproliferative neoplasm (MPN) in mice. We aimed to shed more light on Lyn's role in haematological neoplasm and systematically investigated Lyn expression in MPN, acute and chronic leukaemia subtypes (n = 236). On top, B-cell chronic lymphocytic leukaemia (B-CLL) and chronic myeloid leukaemia significantly overexpressed Lyn when compared to de novo acute lymphoblastic leukaemia, de novo acute myeloid leukaemia (AML) and Philadelphia-chromosome-negative myeloproliferative neoplasms (p < 0.001). Most of acute leukaemia subtypes showed a notable down-regulation of Lyn mRNA but anyhow individual cases were labelled for the active form of Lyn protein. Intriguingly, secondary AML evolved in myelodysplastic syndromes revealed almost undetectable Lyn. Overexpression of Lyn in B-CLL was associated with a significant down-regulation of microRNA-337-5p suggesting that aberrant expression of this particular microRNA could be involved in post-transcriptional control of Lyn mRNA fate. We conclude that tyrosine kinase Lyn contributes to the malignant phenotype in certain leukaemia subtypes and therefore attracts targeted therapy.
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10.56Impact points
Following (8)
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Jürgen Krauter
Medizinische Hochschule Hannover -
Judit Várkonyi
Semmelweis University, Budapest -
Matthias Ballmaier
Medizinische Hochschule Hannover -
Birgitt Wiese
Medizinische Hochschule Hannover -
Ute Modlich
Medizinische Hochschule Hannover
