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| 2. |
- Hofvander, Jakob, et al.
(författare)
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Different patterns of clonal evolution among different sarcoma subtypes followed for up to 25 years
- 2018
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1, s. 3662-
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Tidskriftsartikel (refereegranskat)abstract
- To compare clonal evolution in tumors arising through different mechanisms, we selected three types of sarcoma—amplicon-driven well-differentiated liposarcoma (WDLS), gene fusion-driven myxoid liposarcoma (MLS), and sarcomas with complex genomes (CXS)—and assessed the dynamics of chromosome and nucleotide level mutations by cytogenetics, SNP array analysis and whole-exome sequencing. Here we show that the extensive single-cell variation in WDLS has minor impact on clonal key amplicons in chromosome 12. In addition, only a few of the single nucleotide variants in WDLS were present in more than one lesion, suggesting that such mutations are of little significance in tumor development. MLS displays few mutations other than the FUS-DDIT3 fusion, and the primary tumor is genetically sometimes much more complex than its relapses, whereas CXS in general shows a gradual increase of both nucleotide- and chromosome–level mutations, similar to what has been described in carcinomas.
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| 3. |
- Hofvander, Jakob, et al.
(författare)
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Frequent low-level mutations of protein kinase D2 in angiolipoma
- 2017
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Ingår i: Journal of Pathology. - : WILEY. - 0022-3417 .- 1096-9896. ; 241:5, s. 578-582
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Tidskriftsartikel (refereegranskat)abstract
- Tumours displaying differentiation towards normal fat constitute the most common subgroup of soft tissue neoplasms. A series of such tumours was investigated by whole-exome sequencing followed by targeted ultra-deep sequencing. Eighty per cent of angiolipomas, but not any other tumour type, displayed mutations in the protein kinase D2 (PRKD2) gene, typically in the part encoding the catalytic domain. The absence of other aberrations at the chromosome or RNA level suggests that PRKD2 mutations are critical for angiolipoma development. Consistently, the mutated PRKD2 alleles were present at low (3-15%) frequencies, indicating that only a subset of the tumour cells is affected. Indeed, by sequencing mature fat cells and other cells separately, the former typically showed the highest mutation frequencies. Thus, we hypothesize that altered PRKD2 signalling in the adipocytic cells drives tumourigenesis and, in agreement with its pivotal role in angiogenesis, induces the vessel formation that is characteristic for angiolipoma. Copyright (c) 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley amp; Sons, Ltd.
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| 4. |
- Hofvander, Jakob, et al.
(författare)
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Recurrent PRDM10 Gene Fusions in Undifferentiated Pleomorphic Sarcoma.
- 2015
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 21:4, s. 864-869
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Undifferentiated pleomorphic sarcoma (UPS) is defined as a sarcoma with cellular pleomorphism and no identifiable line of differentiation. It is typically a high-grade lesion with a metastatic rate of about 1/3. No tumor-specific rearrangement has been identified and genetic markers that could be used for treatment stratification are lacking. We performed transcriptome sequencing (RNA-Seq) to search for novel gene fusions. Experimental design: RNA-Seq, fluorescence in situ hybridization, and/or various PCR methodologies were used to search for gene fusions and rearrangements of the PRDM10 gene in 84 soft tissue sarcomas. Results: Using RNA-Seq, two cases of UPS were found to display novel gene fusions, both involving the transcription factor PRDM10 as the 3'-partner and either MED12 or CITED2 as the 5'-partner gene. Further screening of 82 soft tissue sarcomas for rearrangements of the PRDM10 locus, revealed one more UPS with a MED12/PRDM10 fusion. None of these genes has been implicated in neoplasia-associated gene fusions before. Conclusions: Our results suggest that PRDM10-fusions are present in around 5% of UPS. Although the fusion-positive cases in our series showed the same nuclear pleomorphism and lack of differentiation as other UPS, it is noteworthy that all three were morphologically low-grade and that none of the patients developed metastases. Thus, PRDM10 fusion-positive sarcomas may constitute a clinically important subset of UPS.
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| 5. |
- Hofvander, Jakob, et al.
(författare)
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RNA sequencing of sarcomas with simple karyotypes: identification and enrichment of fusion transcripts.
- 2015
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Ingår i: Laboratory Investigation. - : Elsevier BV. - 1530-0307 .- 0023-6837. ; 95:6, s. 603-609
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Tidskriftsartikel (refereegranskat)abstract
- Gene fusions are neoplasia-associated mutations arising from structural chromosomal rearrangements. They have a strong impact on tumor development and constitute important diagnostic markers. Malignant soft tissue tumors (sarcomas) constitute a heterogeneous group of neoplasms with >50 distinct subtypes, each of which is rare. In addition, there is considerable morphologic overlap between sarcomas and benign lesions. Several subtypes display distinct gene fusions, serving as excellent biomarkers. The development of methods for deep sequencing of the complete transcriptome (RNA-Seq) has substantially improved the possibilities for detecting gene fusions. With the aim of identifying new gene fusions of biological and clinical relevance, eight sarcomas with simple karyotypes, ie, only one or a few structural rearrangements, were subjected to massively parallel paired-end sequencing of mRNA. Three different algorithms were used to identify fusion transcripts from RNA-Seq data. Three novel (KIAA2026-NUDT11, CCBL1-ARL1, and AFF3-PHF1) and two previously known fusions (FUS-CREB3L2 and HAS2-PLAG1) were found and could be verified by other methods. These findings show that RNA-Seq is a powerful tool for detecting gene fusions in sarcomas but also suggest that it is advisable to use more than one algorithm to analyze the output data as only two of the confirmed fusions were reported by more than one of the gene fusion detection software programs. For all of the confirmed gene fusions, at least one of the genes mapped to a chromosome band implicated by the karyotype, suggesting that sarcomas with simple karyotypes constitute an excellent resource for identifying novel gene fusions.Laboratory Investigation advance online publication, 13 April 2015; doi:10.1038/labinvest.2015.50.
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| 6. |
- Mandahl, Nils, et al.
(författare)
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Scattered genomic amplification in dedifferentiated liposarcoma
- 2017
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Ingår i: Molecular Cytogenetics. - : Springer Science and Business Media LLC. - 1755-8166. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Atypical lipomatous tumor (ALT), well differentiated liposarcoma (WDLS) and dedifferentiated liposarcoma (DDLS) are cytogenetically characterized by near-diploid karyotypes with no or few other aberrations than supernumerary ring or giant marker chromosomes, although DDLS tend to have somewhat more complex rearrangements. In contrast, pleomorphic liposarcomas (PLS) have highly aberrant and heterogeneous karyotypes. The ring and giant marker chromosomes contain discontinuous amplicons, in particular including multiple copies of the target genes CDK4, HMGA2 and MDM2 from 12q, but often also sequences from other chromosomes. Results: The present study presents a DDLS with an atypical hypertriploid karyotype without any ring or giant marker chromosomes. SNP array analyses revealed amplification of almost the entire 5p and discontinuous amplicons of 12q including the classical target genes, in particular CDK4. In addition, amplicons from 1q, 3q, 7p, 9p, 11q and 20q, covering from 2 to 14 Mb, were present. FISH analyses showed that sequences from 5p and 12q were scattered, separately or together, over more than 10 chromosomes of varying size. At RNA sequencing, significantly elevated expression, compared to myxoid liposarcomas, was seen for TRIO and AMACR in 5p and of CDK4, HMGA2 and MDM2 in 12q. Conclusions: The observed pattern of scattered amplification does not show the characteristics of chromothripsis, but is novel and differs from the well known cytogenetic manifestations of amplification, i.e., double minutes, homogeneously staining regions and ring chromosomes. Possible explanations for this unusual distribution of amplified sequences might be the mechanism of alternative lengthening of telomeres that is frequently active in DDLS and events associated with telomere crisis.
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| 7. |
- Al-Ibraheemi, Alyaa, et al.
(författare)
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Aberrant receptor tyrosine kinase signaling in lipofibromatosis : a clinicopathological and molecular genetic study of 20 cases
- 2019
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Ingår i: Modern Pathology. - : Elsevier BV. - 0893-3952. ; 32:3, s. 423-434
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Tidskriftsartikel (refereegranskat)abstract
- Lipofibromatosis is a rare pediatric soft tissue tumor with predilection for the hands and feet. Previously considered to represent “infantile fibromatosis”, lipofibromatosis has distinctive morphological features, with mature adipose tissue, short fascicles of bland fibroblastic cells, and lipoblast-like cells. Very little is known about the genetic underpinnings of lipofibromatosis. Prompted by our finding of the FN1-EGF gene fusion, previously shown to be a characteristic feature of calcifying aponeurotic fibroma (CAF), in a morphologically typical case of lipofibromatosis that recurred showing features of CAF, we studied a cohort of 20 cases of lipofibromatosis for this and other genetic events. The cohort was composed of 14 males and 6 females (median age 3 years; range 1 month–14 years). All primary tumors showed classical lipofibromatosis morphology. Follow-up disclosed three local recurrences, two of which contained calcifying aponeurotic fibroma-like nodular calcifications in addition to areas of classic lipofibromatosis, and no metastases. By FISH and RNA sequencing, four cases were positive for FN1-EGF and one case each showed an EGR1-GRIA1, TPR-ROS1, SPARC-PDGFRB, FN1-TGFA, EGFR-BRAF, VCL-RET, or HBEGF-RBM27 fusion. FN1-EGF was the only recurrent fusion, suggesting that some cases of “lipofibromatosis” may represent calcifying aponeurotic fibroma lacking hallmark calcifications. Several of the genes involved in fusions (BRAF, EGFR, PDGFRB, RET, and ROS1) encode receptor tyrosine kinases (RTK), or ligands to the RTK EGFR (EGF, HBEGF, TGFA), suggesting a shared deregulation of the PI3K–AKT–mTOR pathway in a large subset of lipofibromatosis cases.
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| 8. |
- Arbajian, Elsa, et al.
(författare)
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In-depth genetic analysis of sclerosing epithelioid fibrosarcoma reveals recurrent genomic alterations and potential treatment targets
- 2017
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 23:23, s. 7426-7434
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Sclerosing epithelioid fibrosarcoma (SEF) is a highly aggressive soft tissue sarcoma closely related to low-grade fibromyxoid sarcoma (LGFMS). Some tumors display morphological characteristics of both SEF and LGFMS, so called hybrid SEF/LGFMS. Despite the overlap of gene fusion variants between these two tumor types, SEF is much more aggressive. The present study aimed to further characterize SEF and hybrid SEF/LGFMS genetically in order to better understand the role of the characteristic fusion genes and possible additional genetic alterations in tumorigenesis.EXPERIMENTAL DESIGN: We performed whole exome sequencing, single nucleotide polymorphism (SNP) array analysis, RNA-sequencing (RNA-seq), global gene expression analyses and/or IHC on a series of 13 SEFs and 6 hybrid SEF/LGFMS. We also expressed the FUS-CREB3L2 and EWSR1-CREB3L1 fusion genes conditionally in a fibroblast cell line; these cells were subsequently analyzed by RNA-seq and expression of the CD24 protein was assessed by FACS analysis.RESULTS: The SNP array analysis detected a large number of structural aberrations in SEF and SEF/LGFMS, many of which were recurrent, notably DMD microdeletions. RNA-seq identified FUS-CREM and PAX5-CREB3L1 as alternative fusion genes in one SEF each. CD24 was strongly upregulated, presumably a direct target of the fusion proteins. This was further confirmed by the gene expression analysis and FACS analysis on Tet-On 3G cells expressing EWSR1-CREB3L1.CONCLUSIONS: While gene fusions are the primary tumorigenic events in both SEF and LGFMS, additional genomic changes explain the differences in aggressiveness and clinical outcome between the two types. CD24 and DMD constitute potential therapeutic targets.
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| 9. |
- Danielsen, Stine A, et al.
(författare)
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Methylated RASSF1A in malignant peripheral nerve sheath tumors identifies neurofibromatosis type 1 patients with inferior prognosis.
- 2015
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Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1523-5866 .- 1522-8517. ; 17:1, s. 63-69
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Tidskriftsartikel (refereegranskat)abstract
- Malignant peripheral nerve sheath tumor (MPNST) is a rare and highly aggressive disease with no evidence of effect from adjuvant therapy. It is further associated with the hereditary syndrome neurofibromatosis type 1 (NF1). Silencing of the tumor suppressor gene RASSF1A through DNA promoter hypermethylation is known to be involved in cancer development, but its impact in MPNSTs remains unsettled.
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| 10. |
- Hofvander, Jakob, et al.
(författare)
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Comprehensive genetic analysis of a pediatric pleomorphic myxoid liposarcoma reveals near-haploidization and loss of the RB1 gene.
- 2016
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Ingår i: Histopathology. - : Wiley. - 0309-0167. ; 69:1, s. 141-147
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Tidskriftsartikel (refereegranskat)abstract
- Pleomorphic myxoid liposarcoma (PML) is an exceptionally rare and poorly studied subtype of liposarcoma, typically occurring in children and adolescents. The few previous genetic studies have shown that PML lacks the gene fusions and amplifications that characterize myxoid liposarcoma, atypical lipomatous tumor, and dedifferentiated liposarcoma. To learn more about its pathogenesis, we performed a comprehensive genetic analysis, including chromosome banding, fluorescence in situ hybridization, single nucleotide polymorphism (SNP) array analysis, deep sequencing of the exome (WES) complemented by targeted sequencing of hotspot regions of selected cancer-associated genes, and transcriptome sequencing (RNA-seq), of a PML in a 10-year-old boy.
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