| 1. |
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| 2. |
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| 3. |
- Andersson, Anna, et al.
(author)
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Gene expression profiling of leukemic cell lines reveals conserved molecular signatures among subtypes with specific genetic aberrations
- 2005
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 19:6, s. 1042-1050
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Journal article (peer-reviewed)abstract
- Hematologic malignancies are characterized by fusion genes of biological/clinical importance. Immortalized cell lines with such aberrations are today widely used to model different aspects of leukemogenesis. Using cDNA microarrays, we determined the gene expression profiles of 40 cell lines as well as of primary leukemias harboring 11q23/MLL rearrangements, t(1;19)[TCF3/PBX1], t(12;21)[ETV6/RUNX1], t(8;21)[RUNX1/CBFA2T1], t(8;14) [IGH@/MYC], t(8;14)[TRA@/MYC], t(9;22)[BCR/ABL1], t(10;11) [PICALM/MLLT10], t(15;17)[PML/RARA], or inv(16)[CBFB/MYH11]. Unsupervised classification revealed that hematopoietic cell lines of diverse origin, but with the same primary genetic changes, segregated together, suggesting that pathogenetically important regulatory networks remain conserved despite numerous passages. Moreover, primary leukemias cosegregated with cell lines carrying identical genetic rearrangements, further supporting that critical regulatory pathways remain intact in hematopoietic cell lines. Transcriptional signatures correlating with clinical subtypes/primary genetic changes were identified and annotated based on their biological/molecular properties and chromosomal localization. Furthermore, the expression profile of tyrosine kinase-encoding genes was investigated, identifying several differentially expressed members, segregating with primary genetic changes, which may be targeted with tyrosine kinase inhibitors. The identified conserved signatures are likely to reflect regulatory networks of importance for the transforming abilities of the primary genetic changes and offer important pathogenetic insights as well as a number of targets for future rational drug design.
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| 4. |
- Andersson, Anna, et al.
(author)
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Microarray-based classification of a consecutive series of 121 childhood acute leukemias: prediction of leukemic and genetic subtype as well as of minimal residual disease status.
- 2007
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 21:6, s. 1198-1203
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Journal article (peer-reviewed)abstract
- Gene expression analyses were performed on 121 consecutive childhood leukemias (87 B-lineage acute lymphoblastic leukemias (ALLs), 11 T-cell ALLs and 23 acute myeloid leukemias (AMLs)), investigated during an 8-year period at a single center. The supervised learning algorithm k-nearest neighbor was utilized to build gene expression predictors that could classify the ALLs/AMLs according to clinically important subtypes with high accuracy. Validation experiments in an independent data set verified the high prediction accuracies of our classifiers. B-lineage ALLs with uncharacteristic cytogenetic aberrations or with a normal karyotype displayed heterogeneous gene expression profiles, resulting in low prediction accuracies. Minimal residual disease status (MRD) in T-cell ALLs with a high (40.1%) MRD at day 29 could be classified with 100% accuracy already at the time of diagnosis. In pediatric leukemias with uncharacteristic cytogenetic aberrations or with a normal karyotype, unsupervised analysis identified two novel subgroups: one consisting mainly of cases remaining in complete remission (CR) and one containing a few patients in CR and all but one of the patients who relapsed. This study of a consecutive series of childhood leukemias confirms and extends further previous reports demonstrating that global gene expression profiling provides a valuable tool for genetic and clinical classification of childhood leukemias.
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| 5. |
- Andersson, Anna, et al.
(author)
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Paired multiplex reverse-transcriptase polymerase chain reaction (PMRT-PCR) analysis as a rapid and accurate diagnostic tool for the detection of MLL fusion genes in hematologic malignancies
- 2001
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In: Leukemia. - 1476-5551. ; 15:8, s. 1293-1293
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Journal article (peer-reviewed)abstract
- The MLL gene in chromosome band 11q23 is frequently rearranged in acute lymphoblastic and acute myeloid leukemias. To date, more than 50 different chromosomal regions are known to participate in translocations involving 11q23, many of which affect MLL. The pathogenetically important outcome of these rearrangements is most likely the creation of a fusion gene consisting of the 5' part of the MLL gene and the 3' end of the partner gene. Although abnormalities of the MLL gene as such are generally associated with poor survival, recent data suggest that the prognostic impact varies among the different fusion genes generated. Hence, detection of the specific chimeric gene produced is important for proper prognostication and clinical decision making. We have developed a paired multiplex reverse-transcriptase polymerase chain reaction analysis to facilitate a rapid and accurate detection of the most frequent MLL fusion genes in adult and childhood acute leukemias. To increase the specificity, two sets of primers were designed for each fusion gene, and these paired primer sets were run in parallel in two separate multiplex one-step PCR reactions. Using the described protocol, we were able to amplify successfully, in one single assay, the six clinically relevant fusion genes generated by the t(4;11)(q21;q23) [MLL/AF4], t(6;11)(q27;q23) [MLL/AF6], t(9;11)(p21-22;q23) [MLL/AF9], t(10;11)(p11-13;q23) [MLL/AF10], t(11;19)(q23;p13.1) [MLL/ELL], and t(11;19)(q23; p13.3) [MLL/ENL] in cell lines, as well as in patient material.
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| 6. |
- Askmyr, Maria, et al.
(author)
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Modeling chronic myeloid leukemia in immunodeficient mice reveals expansion of aberrant mast cells and accumulation of pre-B cells.
- 2014
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In: Blood Cancer Journal. - : Springer Science and Business Media LLC. - 2044-5385. ; 4
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Journal article (peer-reviewed)abstract
- Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that, if not treated, will progress into blast crisis (BC) of either myeloid or B lymphoid phenotype. The BCR-ABL1 fusion gene, encoding a constitutively active tyrosine kinase, is thought to be sufficient to cause chronic phase (CP) CML, whereas additional genetic lesions are needed for progression into CML BC. To generate a humanized CML model, we retrovirally expressed BCR-ABL1 in the cord blood CD34(+) cells and transplanted these into NOD-SCID (non-obese diabetic/severe-combined immunodeficient) interleukin-2-receptor γ-deficient mice. In primary mice, BCR-ABL1 expression induced an inflammatory-like state in the bone marrow and spleen, and mast cells were the only myeloid lineage specifically expanded by BCR-ABL1. Upon secondary transplantation, the pronounced inflammatory phenotype was lost and mainly human mast cells and macrophages were found in the bone marrow. Moreover, a striking block at the pre-B-cell stage was observed in primary mice, resulting in an accumulation of pre-B cells. A similar block in B-cell differentiation could be confirmed in primary cells from CML patients. Hence, this humanized mouse model of CML reveals previously unexplored features of CP CML and should be useful for further studies to understand the disease pathogenesis of CML.
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| 7. |
- Barbouti, Aikaterini, et al.
(author)
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Clinical and genetic studies of ETV6/ABL1-positive chronic myeloid leukaemia in blast crisis treated with imatinib mesylate.
- 2003
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In: British Journal of Haematology. - : Wiley. - 0007-1048. ; 122:1, s. 85-93
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Journal article (peer-reviewed)abstract
- Most chronic myeloid leukaemia (CML) patients are genetically characterized by the t(9;22)(q34;q11), generating the BCR/ABL1 fusion gene. However, a few CML patients with rearrangements of 9q34 and 12p13, leading to ETV6/ABL1 chimaeras, have also been reported. Here we describe the clinical and genetic response to imatinib mesylate treatment of an ETV6/ABL1-positive CML patient diagnosed in blast crisis (BC). A chronic phase was achieved after acute myeloid leukaemia induction therapy. Then, treatment with imatinib mesylate (600 mg/d) was initiated and the effect was assessed clinically as well as genetically, including by repeated interphase fluorescence in situ hybridization studies. Until d 71 of imatinib mesylate therapy, stable improvements in the clinical and laboratory features were noted, and the frequency of ABL1-rearranged peripheral blood cells decreased from 56% to 11%. At d 92, an additional t(12;13)(p12;q13), with the 12p breakpoint proximal to ETV6, was found. The patient relapsed into BC 126 d after the start of the imatinib mesylate treatment and succumbed to the disease shortly afterwards. No mutations in the tyrosine kinase domain of ABL1 of the ETV6/ABL1 fusion were identified in the second BC. However, whereas the ETV6/ABL1 expression was seemingly the same at diagnosis and at second BC, the expression of ETV6 was markedly lower at the second BC. This decreased expression of wild-type ETV6 may have been a contributory factor for the relapse.
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| 8. |
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| 9. |
- Fioretos, Thoas, et al.
(author)
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Fusion of the BCR and the fibroblast growth factor receptor-1 (FGFR1) genes as a result of t(8;22)(p11;q11) in a myeloproliferative disorder: the first fusion gene involving BCR but not ABL
- 2001
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In: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 98:11, s. 558-558
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Journal article (peer-reviewed)abstract
- Constitutive activation of tyrosine kinases as a consequence of chromosomal translocations, forming fusion genes, plays an important role in the development of hematologic malignancies, in particular, myeloproliferative syndromes (MPSs). In this respect, the t(9;22)(q34;q11) that results in the BCR/ABL fusion gene in chronic myeloid leukemia is one of the best-studied examples. The fibroblast growth factor receptor 1 (FGFR1) gene at 8p11 encodes a transmembrane receptor tyrosine kinase and is similarly activated by chromosomal translocations, in which three alternative genes-ZNF198 at 13q12, CEP110 at 9q34, and FOP at 6q27-become fused to the tyrosine kinase domain of FGFR1. These 8p11-translocations are associated with characteristic morphologic and clinical features, referred to as "8p11 MPS." In this study, we report the isolation and characterization of a novel fusion gene in a hematologic malignancy with a t(8;22)(p11;q11) and features suggestive of 8p11 MPS. We show that the breakpoints in the t(8;22) occur within introns 4 and 8 of the BCR and FGFR1 genes, respectively. On the mRNA level, the t(8;22) results in the fusion of BCR exons 1-4 in-frame with the tyrosine kinase domain of FGFR1 as well as in the expression of a reciprocal FGFR1/BCR chimeric transcript. By analogy with data obtained from previously characterized fusion genes involving FGFR1 and BCR/ABL, it is likely that the oligomerization domain contributed by BCR is critical and that its dimerizing properties lead to aberrant FGFR1 signaling and neoplastic transformation.
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| 10. |
- Hakansson, P., et al.
(author)
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Establishment and phenotypic characterization of human U937 cells with inducible P210 BCR/ABL expression reveals upregulation of CEACAM1 (CD66a)
- 2004
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In: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 18:3, s. 538-47
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Journal article (peer-reviewed)abstract
- Chronic myeloid leukemia (CML) is characterized by the expression of the P210 BCR/ABL fusion protein. The molecular mechanisms behind this oncogene-mediated hematological disease are, however, not fully understood. Here, we describe the establishment and phenotypic characterization of U937 cells in which P210 BCR/ABL can be conditionally expressed using tetracycline. The induction of BCR/ABL in the obtained clones resulted in a rapid phosphorylation of the STAT1, STAT3 and STAT5 molecules, consistent with the findings in other model systems. Phenotypic characterization of the clones revealed that BCR/ABL induces a slight decrease in the proliferation and viability, without a marked effect on cell cycle distribution, the rate of apoptosis or on cellular differentiation, as judged by several cell surface markers and capacity to reduce nitro blue tetrazolium. Interestingly, BCR/ABL was found to upregulate the expression of carcinoembryonic-related antigen (CEA)CAM1 (CD66a), which is a plasma membrane-linked glycoprotein belonging to the CEAs and involved in signal transduction and cellular adhesion. The expression of CEACAM1 was reversible upon imatinib treatment in BCR/ABL-expressing U937 cells as well as in BCR/ABL-positive K562 cells. The established cell lines may prove useful in further modeling and dissection of BCR/ABL-induced leukemogenesis.
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| 11. |
- Håkansson, Petra, et al.
(author)
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Gene expression analysis of BCR/ABL1-dependent transcriptional response reveals enrichment for genes involved in negative feedback regulation.
- 2008
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In: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 47:4, s. 267-275
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Journal article (peer-reviewed)abstract
- Philadelphia (Ph) chromosome-positive leukemia is characterized by the BCR/ABL1 fusion protein that affects a wide range of signal transduction pathways. The knowledge about its downstream target genes is, however, still quite limited. To identify novel BCR/ABL1-regulated genes we used global gene expression profiling of several Ph-positive and Ph-negative cell lines treated with imatinib. Following imatinib treatment, the Ph-positive cells showed decreased growth, viability, and reduced phosphorylation of BCR/ABL1 and STAT5. In total, 142 genes were identified as being dependent on BCR/ABL1-mediated signaling, mainly including genes involved in signal transduction, e.g. the JAK/STAT, MAPK, TGFB, and insulin signaling pathways, and in regulation of metabolism. Interestingly, BCR/ABL1 was found to activate several genes involved in negative feedback regulation (CISH, SOCS2, SOCS3, PIM1, DUSP6, and TNFAIP3), which may act to indirectly suppress the tumor promoting effects exerted by BCR/ABL1. In addition, several genes identified as deregulated upon BCR/ABL1 expression could be assigned to the TGFB and NFkB signaling pathways, as well as to reflect the metabolic adjustments needed for rapidly growing cells. Apart from providing important pathogenetic insights into BCR/ABL1-mediated leukemogenesis, the present study also provides a number of pathways/individual genes that may provide attractive targets for future development of targeted therapies. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.
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| 12. |
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| 13. |
- Järås, Marcus, et al.
(author)
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Expression of P190 and P210 BCR/ABL1 in normal human CD34(+) cells induces similar gene expression profiles and results in a STAT5-dependent expansion of the erythroid lineage
- 2009
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In: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 37:3, s. 367-375
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Journal article (peer-reviewed)abstract
- Objective. The P190 and P210 BCR/ABL1 fusion genes are mainly associated with different types of hematologic malignancies, but it is presently unclear whether they are functionally different following expression in primitive human hematopoietic cells. Materials and Methods. We investigated and systematically compared the effects of retroviral P190 BCR/ABL1 and P210 BCR/ABL1 expression on cell proliferation, differentiation, and global gene expression in human CD34(+) cells from cord blood. Results. Expression of either P190 BCR/ABL1 or P210 BCR/ABL1 resulted in expansion of erythroid cells and stimulated erythropoietin-independent burst-forming unit-erythroid colony formation. By using a lentiviral anti-signal transducer and activator of transcription 5 (STAT5) short-hairpin RNA, we found that both P190 BCR/ABL1- and P210 BCR/ABL1-induced erythroid cell expansion were STAT5-dependent. Under in vitro conditions favoring B-cell differentiation, neither P190 nor P210 BCR/ABL1-expressing cells formed detectable levels of CD19-positive cells. Gene expression profiling revealed that P190 BCR/ABL1 and P210 BCR/ABL1 induced almost identical gene expression profiles. Conclusions. Our data suggest that the early cellular and transcriptional effects of P190 BCR/ABL1 and P210 BCR/ABL1 expression are very similar when they are expressed in the same human progenitor cell population, and that STAT5 is an important regulator of BCR/ABL1-induced erythroid cell expansion. (C) 2009 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc.
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| 14. |
- Järås, Marcus, et al.
(author)
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Isolation and killing of candidate chronic myeloid leukemia stem cells by antibody targeting of IL-1 receptor accessory protein.
- 2010
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In: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 107:37, s. 16280-16285
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Journal article (peer-reviewed)abstract
- Chronic myeloid leukemia (CML) is genetically characterized by the Philadelphia (Ph) chromosome, formed through a reciprocal translocation between chromosomes 9 and 22 and giving rise to the constitutively active tyrosine kinase P210 BCR/ABL1. Therapeutic strategies aiming for a cure of CML will require full eradication of Ph chromosome-positive (Ph(+)) CML stem cells. Here we used gene-expression profiling to identify IL-1 receptor accessory protein (IL1RAP) as up-regulated in CML CD34(+) cells and also in cord blood CD34(+) cells as a consequence of retroviral BCR/ABL1 expression. To test whether IL1RAP expression distinguishes normal (Ph(-)) and leukemic (Ph(+)) cells within the CML CD34(+)CD38(-) cell compartment, we established a unique protocol for conducting FISH on small numbers of sorted cells. By using this method, we sorted cells directly into drops on slides to investigate their Ph-chromosome status. Interestingly, we found that the CML CD34(+)CD38(-)IL1RAP(+) cells were Ph(+), whereas CML CD34(+)CD38(-)IL1RAP(-) cells were almost exclusively Ph(-). By performing long-term culture-initiating cell assays on the two cell populations, we found that Ph(+) and Ph(-) candidate CML stem cells could be prospectively separated. In addition, by generating an anti-IL1RAP antibody, we provide proof of concept that IL1RAP can be used as a target on CML CD34(+)CD38(-) cells to induce antibody-dependent cell-mediated cytotoxicity. This study thus identifies IL1RAP as a unique cell surface biomarker distinguishing Ph(+) from Ph(-) candidate CML stem cells and opens up a previously unexplored avenue for therapy of CML.
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| 15. |
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| 16. |
- Karrman, Kristina, et al.
(author)
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The t(X;7)(q22;q34) in paediatric T-cell acute lymphoblastic leukaemia results in overexpression of the insulin receptor substrate 4 gene through illegitimate recombination with the T-cell receptor beta locus.
- 2009
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In: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 144, s. 546-551
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Journal article (peer-reviewed)abstract
- Summary The t(X;7)(q22;q34), a translocation not previously reported in a neoplastic disorder, was identified and molecularly characterised in a paediatric T-cell acute lymphoblastic leukaemia (T-ALL), subsequently shown also to harbour a deletion of 6q, a STIL/TAL1 fusion and an activating NOTCH1 mutation. The t(X;7) was further investigated using fluorescence in situ hybridisation (FISH), real-time quantitative polymerase chain reaction (RQ-PCR) and Western blot analyses. FISH revealed a breakpoint at the T-cell receptor beta locus at 7q34 and mapped the corresponding breakpoint to Xq22.3. The latter region contains only two known genes, namely insulin receptor substrate 4 (IRS4) and collagen, type IV, alpha 5 (COL4A5), the expressions of which were analysed by the use of RQ-PCR. COL4A5 was not differentially expressed in the t(X;7)-positive sample compared to five T-ALL controls. However, a marked, 1000-fold overexpression of IRS4 was identified. Western blot analysis with a monoclonal antibody against IRS4 showed overexpression also at the protein level. Considering that forced expression of several members of the IRS family has been shown to result in increased cell proliferation, for example in haematopoietic cells, we hypothesise that the IRS4 up-regulation in T-ALL is pathogenetically important as a mitogenic stimulus.
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| 17. |
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| 18. |
- Larsson, Nina, et al.
(author)
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Genetic analysis of dasatinib-treated chronic myeloid leukemia rapidly developing into acute myeloid leukemia with monosomy 7 in Philadelphia-negative cells.
- 2010
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In: Cancer Genetics and Cytogenetics. - : Elsevier BV. - 0165-4608. ; 199:2, s. 89-95
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Journal article (peer-reviewed)abstract
- Despite the recent success of tyrosine kinase inhibitors (TKIs) in the treatment of chronic myeloid leukemia (CML), approximately 2-17% of patients develop clonal cytogenetic changes in the Philadelphia-negative (Ph(-)) cell population. A fraction of these patients, in particular those displaying trisomy 8 or monosomy 7, are at risk of developing a myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Consequently, there is a need to characterize the clinical features of such cases and to increase our understanding of the pathogenetic mechanisms underlying the emergence of clonal cytogenetic changes in Ph(-) cells. To date, most cases reported have received treatment with imatinib. Here we describe the case of a patient with CML who developed monosomy 7 in Ph(-) cells during dasatinib therapy. At 20 months after dasatinib initiation, the patient developed MDS, which rapidly progressed into AML. Genome-wide 500K SNP array analysis of the monosomy 7 clone revealed no acquired submicroscopic copy number changes. Given the strong association between monosomy 7 and mutation of genes involved in the RAS pathway in juvenile myelomonocytic leukemia, we also screened for pathogenetic variants in KRAS, NRAS, and PTPN11, but did not detect any changes.
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| 19. |
- Larsson, Nina, et al.
(author)
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Myeloid malignancies with acquired trisomy 21 as the sole cytogenetic change are clinically highly variable and display a heterogeneous pattern of copy number alterations and mutations(a).
- 2012
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In: European Journal of Haematology. - : Wiley. - 1600-0609 .- 0902-4441. ; 88:2, s. 136-143
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Journal article (peer-reviewed)abstract
- Objectives: Acquired trisomy 21 is one of the most common numerical abnormalities in acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), myeloproliferative neoplasms (MPN), and MDS/MPN; however, little is known about its pathogenic impact, accompanying submicroscopic changes, and its relation to other clinical features. Furthermore, previous studies addressing this issue have mainly focused on cases in which +21 was part of a complex karyotype. Methods: We ascertained the incidence of +21, both as a sole change (T21s) and irrespective of additional changes (T21all), in relation to disease type, morphologic subgroup, gender, and age in all published AML, MDS, MPN, and MDS/MPN cases. Furthermore, single nucleotide polymorphism (SNP) array analysis was performed on 11 myeloid malignancies with T21s, followed by mutation analysis of the FGFR1, FLT3, GATA1, JAK2, KIT, NPM1, NRAS, RUNX1, and TET2 genes. Results: The frequencies of T21s and/or T21all varied significantly among the AML, MDS, MPN and MDS/MPN cases, among the AML and MPN subtypes, and in relation to the age of the AML, MDS, and MPN patients. In the 11 cases analyzed by SNP array, a total of nine genomic imbalances, comprising seven deletions and two duplications, were identified in six cases; none of the alterations were recurrent. Partial uniparental disomies (UPDs) were found in five cases; two recurrent UPDs were identified, namely UPD4q and UPD7q. Mutations in NPM1, RUNX1, and TET2 were detected in five cases, three of which harboured a pathogenic RUNX1 mutation. The TET2 mutation was found in one of the cases with UPD4q. Conclusions: The results show that trisomy 21-positive myeloid malignancies are clinically highly variable and that they display a heterogeneous pattern of copy number alterations and mutations.
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| 20. |
- Lilljebjörn, Henrik, et al.
(author)
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Combined high-resolution array-based comparative genomic hybridization and expression profiling of ETV6/RUNX1-positive acute lymphoblastic leukemias reveal a high incidence of cryptic Xq duplications and identify several putative target genes within the commonly gained region
- 2007
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 21:10, s. 2137-2144
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Journal article (peer-reviewed)abstract
- Seventeen ETV6/RUNX1-positive pediatric acute lymphoblastic leukemias were investigated by high-resolution array-based comparative genomic hybridization ( array CGH), gene expression profiling and fluorescence in situ hybridization. Comparing the array CGH and gene expression patterns revealed that genomic imbalances conferred a great impact on the expression of genes in the affected regions. The array CGH analyses identified a high frequency of cytogenetically cryptic genetic changes, for example, del(9p) and del(12p). Interestingly, a duplication of Xq material, varying between 30 and 60Mb in size, was found in 6 of 11 males (55%), but not in females. Genes on Xq were found to have a high expression level in cases with dup(Xq); a similar overexpression was confirmed in t(12;21)-positive cases in an external gene expression data set. By studying the expression profile and the proposed function of genes in the minimally gained region, several candidate target genes (SPANXB, HMGB3, FAM50A, HTATSF1 and RAP2C) were identified. Among them, the testis-specific SPANXB gene was the only one showing a high and uniform overexpression, irrespective of gender and presence of Xq duplication, suggesting that this gene plays an important pathogenetic role in t(12;21)-positive leukemia.
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| 21. |
- Lilljebjörn, Henrik, et al.
(author)
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Whole-exome sequencing of pediatric acute lymphoblastic leukemia
- 2012
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In: Leukemia. - : Nature Publishing Group. - 0887-6924 .- 1476-5551. ; 26:7, s. 1602-1607
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Journal article (peer-reviewed)abstract
- Acute lymphoblastic leukemia (ALL), the most common malignant disorder in childhood, is typically associated with numerical chromosomal aberrations, fusion genes or small focal deletions, thought to represent important pathogenetic events in the development of the leukemia. Mutations, such as single nucleotide changes, have also been reported in childhood ALL, but these have only been studied by sequencing a small number of candidate genes. Herein, we report the first unbiased sequencing of the whole exome of two cases of pediatric ALL carrying the ETV6/RUNX1 (TEL/AML1) fusion gene (the most common genetic subtype) and corresponding normal samples. A total of 14 somatic mutations were identified, including four and seven protein-altering nucleotide substitutions in each ALL. Twelve mutations (86%) occurred in genes previously described to be mutated in other types of cancer, but none was found to be recurrent in an extended series of 29 ETV6/RUNX1-positive ALLs. The number of single nucleotide mutations was similar to the number of copy number alterations as detected by single nucleotide polymorphism arrays. Although the true pathogenetic significance of the mutations must await future functional evaluations, this study provides a first estimate of the mutational burden at the genetic level of t(12;21)-positive childhood ALL.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
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| 26. |
- Storlazzi, Clelia T, et al.
(author)
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Identification of a commonly amplified 4.3 Mb region with overexpression of C8FW, but not MYC in MYC-containing double minutes in myeloid malignancies
- 2004
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 13:14, s. 1479-1485
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Journal article (peer-reviewed)abstract
- Double minutes (dmin), the cytogenetic hallmark of genomic amplification, are found in ∼1% of karyotypically abnormal acute myelold leukemias (AML) and myelodysplastic syndromes (MDS). The MYC gene at 8q24 has been reported to be amplified in the majority of the cases, and generally it has been assumed that MYC is the target gene. However, only a few studies have focused on the extent of the amplicon or on the expression patterns of the amplified genes. We have studied six cases (five AML and one MDS) with MYC-containing dmin. Detailed fluorescence in situ hybridization analyses identified a common 4.3 Mb amplicon, with clustered proximal and distal breakpoints, harboring eight known genes (C8FW, NSE2, POU5FLC20, MYC, PVT1, AK093424, MGC27434 and MLZE). The corresponding region was deleted in one of the chromosome 8 homologues in five of the six cases, suggesting that the dmin originated through extra replication (or loop-formation)-excision-amplification. Northern blot analysis revealed that MYC was not overexpressed. Instead, the C8FW gene, encoding a phosphoprotein regulated by mitogenic pathways, displayed increased expression. These results exclude MYC as the target gene and indicate that overexpression of C8FW may be the functionally important consequence of 8q24 amplicons in AML and MDS. © Oxford University Press 2004, all rights reserved.
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| 27. |
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| 28. |
- Svensson, Emelie, et al.
(author)
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Deregulation of the Wilms' tumour gene 1 protein (WT1) by BCR/ABL1 mediates resistance to imatinib in human leukaemia cells
- 2007
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 21:12, s. 2485-2494
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Journal article (peer-reviewed)abstract
- The Wilms' tumour gene 1 (WT1) protein is highly expressed in most leukaemias. Co-expression of WT1 and the fusion protein AML1-ETO in mice rapidly induces acute myeloid leukaemia (AML). Mechanisms behind expression of WT1, as well as consequences thereof, are still unclear. Here, we report that the fusion protein BCR/ABL1 increases expression of WT1 mRNA and protein via the phosphatidylinositol-3 kinase (PI3K)-Akt pathway. Inhibition of BCR/ABL1 or PI3K activity strongly suppressed transcription from WT1 promoter/enhancer reporters. Forced expression of BCR/ABL1 in normal human progenitor CD34+ cells increased WT1 mRNA and protein, further supporting the notion of BCR/ABL1-driven expression of WT1 in human haematopoietic cells. Forced expression of WT1 in K562 cells provided protection against cytotoxic effects of the ABL1 tyrosine kinase inhibitor imatinib, as judged by effects on viability measured by trypan blue exclusion, metabolic activity, annexin V and DAPI (4', 6-diamidino-2-phenylindole) staining. None of the isoforms provided any detectable protection against apoptosis induced by arsenic trioxide and only very weak protection against etoposide, indicating that WT1 interferes with specific apoptotic signalling pathways. Our data demonstrate that WT1 expression is induced by oncogenic signalling from BCR/ABL1 and that WT1 contributes to resistance against apoptosis induced by imatinib.
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| 29. |
- Ågerstam, Helena, et al.
(author)
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Fusion gene-mediated truncation of RUNX1 as a potential mechanism underlying disease progression in the 8p11 myeloproliferative syndrome.
- 2007
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In: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 46:7, s. 635-643
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Journal article (peer-reviewed)abstract
- The 8p11 myeloproliferative syndrome (EMS) is a chronic myeloproliferative disorder molecularly characterized by fusion of various 5' partner genes to the 3' part of the fibroblast growth factor receptor 1 (FGFR1) gene at 8p, resulting in constitutive activation of the tyrosine kinase activity contained within FGFR1. EMS is associated with a high risk of transformation to acute myeloid leukemia (AML), but the mechanisms underlying the disease progression are unknown. In the present study, we have investigated a case of EMS harboring a t(8;22)(p11; q11)/BCR-FGFR1 rearrangement as well as a t(9;21)(q34;q22) at the time of AML transformation. FISH and RT-PCR analyses revealed that the t(9;21) leads to a fusion gene consisting of the 5' part of RUNX1 (exons 1-4) fused to repetitive sequences of a gene with unknown function on chromosome 9, adding 70 amino acids to RUNX1 exon 4. The t(9;21) hence results in a truncation of RUNX1. No point mutations were found in the other RUNX1 allele. The most likely functional outcome of the rearrangement was haploinsufficiency of RUNX1, which thus may be one mechanism by which EMS transforms to AML. (c) 2007 Wiley-Liss, Inc.
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| 30. |
- Ågerstam, Helena, et al.
(author)
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Modeling the human 8p11-myeloproliferative syndrome in immunodeficient mice
- 2010
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In: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 116:12, s. 2103-2111
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Journal article (peer-reviewed)abstract
- The 8p11 myeloproliferative syndrome (EMS), also referred to as stem cell leukemia/lymphoma, is a chronic myeloproliferative disorder that rapidly progresses into acute leukemia. Molecularly, EMS is characterized by fusion of various partner genes to the FGFR1 gene, resulting in constitutive activation of the tyrosine kinases in FGFR1. To date, no previous study has addressed the functional consequences of ectopic FGFR1 expression in the potentially most relevant cellular context, that of normal primary human hematopoietic cells. Herein, we report that expression of ZMYM2/FGFR1 (previously known as ZNF198/FGFR1) or BCR/FGFR1 in normal human CD34(+) cells from umbilicalcord blood leads to increased cellular proliferation and differentiation toward the erythroid lineage in vitro. In immunodeficient mice, expression of ZMYM2/FGFR1 or BCR/FGFR1 in human cells induces several features of human EMS, including expansion of several myeloid cell lineages and accumulation of blasts in bone marrow. Moreover, bone marrow fibrosis together with increased extramedullary hematopoiesis is observed. This study suggests that FGFR1 fusion oncogenes, by themselves, are capable of initiating an EMS-like disorder, and provides the first humanized model of a myeloproliferative disorder transforming into acute leukemia in mice. The established in vivo EMS model should provide a valuable tool for future studies of this disorder. (Blood. 2010;116(12):2103-2111)
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| 31. |
- Åman, Pierre, et al.
(author)
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Expression patterns of the human sarcoma-associated genes FUS and EWS and the genomic structure of FUS
- 1996
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In: Genomics. - : Elsevier BV. - 1089-8646 .- 0888-7543. ; 37:1, s. 1-8
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Journal article (peer-reviewed)abstract
- FUS (TLS) was first identified as the 5'-part of a fusion gene with CHOP (GADD153, DDIT3) in myxoid liposarcomas with t(12; 16)(q13; p11). Homologies were found with the EWS oncogene, which is rearranged in Ewing sarcomas and other neoplasias. The genomic structure of FUS shows extensive similarities with that of EWS, but the exon/intron structures differ in the 5' parts, and overall FUS is smaller than EWS. Exon 3 of FUS corresponds to exons 3 and 4 in EWS. FUS exons 4-6 correspond to EWS exons 5-8. Exons 7 to 15 of FUS are very similar to those in EWS, although the EWS exons are larger than the corresponding FUS exons. FUS and EWS were expressed in all tissues investigated. The transcripts were stable within the 160-min half-life experiments. No or little variation in FUS or EWS expression was seen when resting lymphocytes were activated. These observations indicate that FUS and EWS belong to the housekeeping type of genes. This view is supported by the presence of the housekeeping gene type of promoter region in both genes.
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