| 1. |
- 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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| 2. |
- Arbajian, Elsa, et al.
(författare)
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A Benign Vascular Tumor With a New Fusion Gene: EWSR1-NFATC1 in Hemangioma of the Bone.
- 2013
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Ingår i: American Journal of Surgical Pathology. - 1532-0979. ; 37:4, s. 613-616
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Tidskriftsartikel (refereegranskat)abstract
- The EWSR1 gene in chromosome band 22q12 is a promiscuous fusion partner involved in a vast array of tumors characterized by gene fusions. In this study, we report the finding of a new fusion gene, EWSR1-NFATC1, in a hemangioma of the bone; genetic rearrangements have not previously been described in this tumor type. Chromosome banding analysis showed a t(18;22)(q23;q12) translocation as the sole change. Fluorescence in situ hybridization mapping suggested the involvement of each of the 2 partner genes, and reverse transcriptase polymerase chain reaction revealed an in-frame EWSR1-NFATC1 transcript. NFATC1 has not previously been shown to be involved in a fusion chimera. However, NFATC2, encoding another member of the same protein family, is known to be a fusion partner for EWSR1 in a subgroup of Ewing sarcoma. Thus, our findings further broaden the spectrum of neoplasms associated with EWSR1 fusion genes, add a new partner to the growing list of EWSR1 chimeras, and suggest that chromosomal rearrangements of pathogenetic, and possibly also diagnostic, significance can be present in benign vascular bone tumors.
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| 3. |
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| 4. |
- Arbajian, Elsa, et al.
(författare)
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Deep sequencing of myxoinflammatory fibroblastic sarcoma
- 2020
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 59:5, s. 309-317
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Tidskriftsartikel (refereegranskat)abstract
- Myxoinflammatory fibroblastic sarcoma (MIFS) has recurrent genetic features in the form of a translocation t(1;10)(p22-31;q24-25), BRAF gene fusions, and/or an amplicon in 3p11-12 including the VGLL3 gene. The breakpoints on chromosomes 1 and 10 in the t(1;10) cluster in or near the TGFBR3 and OGA genes, respectively. We here used a combination of deep sequencing of the genome (WGS), captured sequences (Cap-seq), and transcriptome (RNA-seq) and genomic arrays to investigate the molecular outcome of the t(1;10) and the VGLL3 amplicon, as well as to assess the spectrum of other recurrent genomic features in MIFS. Apart from a ROBO1-BRAF chimera in a t(1;10)-negative MIFS-like tumor, no fusion gene was found at RNA-seq. This was in line with WGS and Cap-seq results, revealing variable breakpoints in chromosomes 1 and 10 and genomic breakpoints that should not yield functional fusion transcripts. The most common genomic rearrangements were breakpoints in or around the OGA, NPM3, and FGF8 genes in chromosome band 10q24, and loss of 1p11-p21 and 10q26-qter (all simultaneously present in 6/7 MIFS); a breakpoint in or near TGFBR3 in chromosome 1 was found in four of these tumors. Amplification and overexpression of VGLL3 was a consistent feature in MIFS and MIFS-like tumors with amplicons in 3p11-12. The significant molecular genetic outcome of the recurrent t(1;10) could be loss of genetic material from 1p and 10q. Other recurrent genomic imbalances in MIFS, such as homozygous loss of CDKN2A and 3p- and 13q-deletions, are shared with other sarcomas, suggesting overlapping pathogenetic pathways. This article is protected by copyright. All rights reserved.
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| 5. |
- 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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| 6. |
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| 7. |
- Arbajian, Elsa, et al.
(författare)
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Methylation patterns and chromatin accessibility in neuroendocrine lung cancer
- 2020
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 12:8, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- Lung cancer is the worldwide leading cause of death from cancer. Epigenetic modifications such as methylation and changes in chromatin accessibility are major gene regulatory mechanisms involved in tumorigenesis and cellular lineage commitment. We aimed to characterize these processes in the context of neuroendocrine (NE) lung cancer. Illumina 450K DNA methylation data were collected for 1407 lung cancers including 27 NE tumors. NE differentially methylated regions (NE-DMRs) were identified and correlated with gene expression data for 151 lung cancers and 31 human tissue entities from the Genotype-Tissue Expression (GTEx) consortium. Assay for transposase-accessible chromatin sequencing (ATAC-seq) and RNA sequencing (RNA-seq) were performed on eight lung cancer cell lines, including three NE cell lines, to identify neuroendocrine specific gene regulatory elements. We identified DMRs with methylation patterns associated with differential gene expression and an NE tumor phenotype. DMR-associated genes could further be split into six functional modules, including one highly specific gene module for NE lung cancer showing high expression in both normal and malignant brain tissue. The regulatory potential of NE-DMRs was further validated in vitro using paired ATAC-and RNA-seq and revealed both proximal and distal regulatory elements of canonical NE-marker genes such as CHGA, NCAM1, INSM1, as well as a number of novel candidate markers of NE lung cancer. Using multilevel genomic analyses of both tumor bulk tissue and lung cancer cell lines, we identified a large catalogue of gene regulatory elements related to the NE phenotype of lung cancer.
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| 8. |
- Arbajian, Elsa
(författare)
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Pathogenetic Mechanisms in Soft Tissue Tumors
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Soft tissue tumors (STT) constitute a heterogeneous group of tumors that arise in tissues of mesenchymal origin. They are currently classified according to morphology and resemblance to normal tissue into over 100 subtypes. Differentiation between the different subtypes can sometimes be difficult, and along with the fact that little is known about the mechanisms of STT development, this makes adequate diagnosis and treatment challenging. In the present thesis, three different pathogenetic mechanisms involved in STT development are investigated and the included studies illustrate each of these mechanisms. In articles I and II, sclerosing epithelioid fibrosarcoma (SEF) and hybrid SEF/low grade fibromyxoid sarcoma (LGFMS) are genetically characterized by the predominant fusion gene variants they harbor. We conclude that the respective fusion genes found in SEF, hybrid SEF/LGFMS and LGFMS are most likely the primary tumorigenic event and that the clinical differences can be explained by the difference in genomic imbalances and aberrations. Additionally, DMD and CD24 are identified as potential therapeutic targets in SEF. In article III, the genetics of angiolipomas are investigated by ultra-deep DNA-sequencing and RNA-sequencing, identifying low-level PRKD2 mutations as the sole genetic abnormality. We demonstrate that the mutations are enriched in mature fat cells and that they affect the catalytic domain of PRKD2, leading to increased proliferation of adipocytic cells and formation of a distorted capillary network. Thus, PRKD2 mutations are probably the driver events in angiolipoma formation. In article IV; we establish that ILMS is a distinct nosologic entity characterized by non-random near-haploidization and few other somatic mutations. Our results indicate that near-haploidization is the main tumorigenic event. We also show that ILMS has a primitive myogenic gene expression signature, providing support for it being classified as a myogenic tumor.In conclusion, studying the mechanisms behind sarcoma development enables the identification of characteristic or even specific diagnostic markers and potential therapeutic targets. This paves the way for individualizing cancer treatment and thus has major implications for treatment outcome and patient well-being.
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| 9. |
- Arbajian, Elsa, et al.
(författare)
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Recurrent EWSR1-CREB3L1 Gene Fusions in Sclerosing Epithelioid Fibrosarcoma.
- 2014
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Ingår i: American Journal of Surgical Pathology. - 1532-0979. ; 38:6, s. 801-808
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Tidskriftsartikel (refereegranskat)abstract
- Sclerosing epithelioid fibrosarcoma (SEF) and low-grade fibromyxoid sarcoma (LGFMS) are 2 distinct types of sarcoma, with a subset of cases showing overlapping morphologic and immunohistochemical features. LGFMS is characterized by expression of the MUC4 protein, and about 90% of cases display a distinctive FUS-CREB3L2 gene fusion. In addition, SEF is often MUC4 positive, but is genetically less well studied. Fluorescence in situ hybridization (FISH) studies have shown involvement of the FUS gene in the majority of so-called hybrid LGFMS/SEF and in 10% to 25% of sarcomas with pure SEF morphology. In this study, we investigated a series of 10 primary tumors showing pure SEF morphology, 4 cases of LGFMS that at local or distant relapse showed predominant SEF morphology, and 1 primary hybrid LGFMS/SEF. All but 1 case showed diffuse expression for MUC4. Using FISH, reverse transcription polymerase chain reaction, and/or mRNA sequencing in selected cases, we found recurrent EWSR1-CREB3L1 fusion transcripts by reverse transcription polymerase chain reaction in 3/10 pure SEF cases and splits and deletions of the EWSR1 and/or CREB3L1 genes by FISH in 6 additional cases. All 5 cases of LGFMS with progression to SEF morphology or hybrid features had FUS-CREB3L2 fusion transcripts. Our results indicate that EWSR1 and CREB3L1 rearrangements are predominant over FUS and CREB3L2 rearrangements in pure SEF, highlighting that SEF and LGFMS are different tumor types, with different impacts on patient outcome.
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| 10. |
- Bekers, Elise M., et al.
(författare)
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Soft tissue angiofibroma : Clinicopathologic, immunohistochemical and molecular analysis of 14 cases
- 2017
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Ingår i: Genes Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 56:10, s. 750-757
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Tidskriftsartikel (refereegranskat)abstract
- Soft tissue angiofibroma is rare and has characteristic histomorphological and genetic features. For diagnostic purposes, there are no specific antibodies available. Fourteen lesions (6 females, 8 males; age range 7-67 years) of the lower extremities (12) and trunk (2) were investigated by immunohistochemistry, including for the first time NCOA2. NCOA2 was also tested in a control group of other spindle cell lesions. The known fusion-genes (AHRR-NCOA2 and GTF2I-NCOA2) were examined using RT-PCR in order to evaluate their diagnostic value. Cases in which no fusion gene was detected were additionally analysed by RNA sequencing. All cases tested showed nuclear expression of NCOA2. However, this was not specific since other spindle cell neoplasms also expressed this marker in a high percentage of cases. Other variably positive markers were EMA, SMA, desmin and CD34. STAT6 was negative in the cases tested. By RT-PCR for the most frequently observed fusions, an AHRR-NCOA2 fusion transcript was found in 9/14 cases. GTF2I-NCOA2 was not detected in the remaining cases (n = 3). RNA sequencing revealed three additional positive cases; two harbored a AHRR-NCOA2 fusion and one case a novel GAB1-ABL1 fusion. Two cases failed molecular analysis due to poor RNA quality. In conclusion, the AHRR-NCOA2 fusion is a frequent finding in soft tissue angiofibroma, while GTF2I-NCOA2 seems to be a rare genetic event. For the first time, we report a GAB1-ABL1 fusion in a soft tissue angiofibroma of a child. Nuclear expression of NCOA2 is not discriminating when compared with other spindle cell neoplasms.
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