| 1. |
- Fransson, Susanne, 1975, et al.
(författare)
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Estimation of copy number aberrations: Comparison of exome sequencing data with SNP microarrays identifies homozygous deletions of 19q13.2 and iin neuroblastoma
- 2016
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Ingår i: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 48:3, s. 1103-1116
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Tidskriftsartikel (refereegranskat)abstract
- In the pediatric cancer neuroblastoma, analysis of recurrent chromosomal aberrations such as loss of chromosome 1p, 11q, gain of 17q and MYCN amplification are used for patient stratification and subsequent therapy decision making. Different analysis techniques have been used for detection of segmental abnormalities, including fluorescence in situ hybridization (FISH), comparative genomic hybridization (CGH)-microarrays and multiplex ligation-dependent probe amplification (MLPA). However, as next-generation sequencing becomes available for clinical use, this technique could also be used for assessment of copy number alterations simultaneously with mutational analysis. In this study we compare genomic profiles generated through exome sequencing data with profiles generated from high resolution Affymetrix single nucleotide polymorphism (SNP) microarrays on 30 neuroblastoma tumors of different stages. Normalized coverage reads for tumors were calculated using Control-FREEC software and visualized through a web based Shiny application, prior to comparison with corresponding SNP-microarray data. The two methods show high-level agreement for breakpoints and copy number of larger segmental aberrations and numerical aneuploidies. However, several smaller gene containing deletions that could not readily be detected through the SNP-microarray analyses were identified through exome profiling, most likely due to difference between spatial distribution of microarray probes and targeted regions of the exome capture. These smaller aberrations included focal ATRX deletion in two tumors and three cases of novel deletions in chromosomal region 19q13.2 causing homozygous loss of multiple genes including the CIC (Capicua) gene. In conclusion, genomic profiles generated from normalized coverage of exome sequencing show concordance with SNP microarray generated genomic profiles. Exome sequencing is therefore a useful diagnostic tool for copy number variant (CNV) detection in neuroblastoma tumors, especially considering the combination with mutational screening. This enables detection of theranostic targets such as ALK and ATRX together with detection of significant segmental aneuploidies, such as 2p-gain, 17q-gain, 11q-deletion as well as MYCN amplification.
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| 2. |
- Fransson, Susanne, 1975, et al.
(författare)
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Intragenic anaplastic lymphoma kinase (ALK) rearrangements: Translocations as a novel mechanism of ALK activation in neuroblastoma tumors.
- 2015
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Ingår i: Genes, chromosomes & cancer. - : Wiley. - 1098-2264 .- 1045-2257. ; 54:2, s. 99-109
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Tidskriftsartikel (refereegranskat)abstract
- Anaplastic lymphoma kinase (ALK) has been demonstrated to be deregulated in sporadic as well as in familiar cases of neuroblastoma (NB). Whereas ALK-fusion proteins are common in lymphoma and lung cancer, there are few reports of ALK rearrangements in NB indicating that ALK mainly exerts its oncogenic capacity via activating mutations and/or overexpression in this tumor type. In this study, 332 NB tumors and 13 cell lines were screened by high resolution single nucleotide polymorphism microarray. Gain of 2p was detected in 23% (60/332) of primary tumors and 46% (6/13) of cell lines, while breakpoints at the ALK locus were detected in four primary tumors and two cell lines. These were further analyzed by next generation sequencing and a targeted enrichment approach. Samples with both ALK and MYCN amplification displayed complex genomic rearrangements with multiple breakpoints within the amplicon. None of the translocations characterized in primary NB tumors are likely to result in a chimeric protein. However, immunohistochemical analysis reveals high levels of phosphorylated ALK in these samples despite lack of initial exons, possibly due to alternative transcription initiation sites. Both ALK proteins predicted to arise from such alterations and from the abnormal ALK exon 4-11 deletion observed in the CLB-BAR cell line show strong activation of downstream targets STAT3 and extracellular signal-regulated kinase (ERK) when expressed in PC12 cells. Taken together, our data indicate a novel, although rare, mechanism of ALK activation with implications for NB tumorigenesis.
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| 3. |
- Javanmardi, Niloufar, et al.
(författare)
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Analysis of ALK, MYCN, and the ALK ligand ALKAL2 (FAM150B/AUG alpha) in neuroblastoma patient samples with chromosome arm 2p rearrangements
- 2020
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Ingår i: Genes Chromosomes & Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 59:1, s. 50-57
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Tidskriftsartikel (refereegranskat)abstract
- Gain of chromosome arm 2p is a previously described entity in neuroblastoma (NB). This genomic address is home to two important oncogenes in NB-MYCN and anaplastic lymphoma kinase (ALK). MYCN amplification is a critical prognostic factor coupled with poor prognosis in NB. Mutation of the ALK receptor tyrosine kinase has been described in both somatic and familial NB. Here, ALK activation occurs in the context of the full-length receptor, exemplified by activating point mutations in NB. ALK overexpression and activation, in the absence of genetic mutation has also been described in NB. In addition, the recently identified ALK ligand ALKAL2 (previously described as FAM150B and AUG alpha) is also found on the distal portion of 2p, at 2p25. Here we analyze 356 NB tumor samples and discuss observations indicating that gain of 2p has implications for the development of NB. Finally, we put forward the hypothesis that the effect of 2p gain may result from a combination of MYCN, ALK, and the ALK ligand ALKAL2.
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| 4. |
- Javanmardi, Niloufar
(författare)
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Genomic instability and genetic heterogeneity in neuroblastoma tumours
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neuroblastoma (NB), a tumour of the sympathetic nervous system and the most common malignant disease of early childhood, is responsible for 9% of paediatric cancer related deaths. Aggressive NB still constitutes a major clinical problem with survival rates of about 35%. It is therefore of great clinical interest to further study the biological parameters that can (i) better classify tumours so that the children may be given the right treatment (ii) identify new actionable targets. Aim - the objective of this thesis was to explore genes and chromosomal regions with potential involvement in the initiation/progression of NB that can be used for improved patient stratification. Results – In paper I and III we detected point mutations in the tyrosine kinase domain of the ALK oncogene. Minor population of cells with ALK mutations were detected with massive parallel deep DNA sequencing. It is likely that early detection of subclones with ALK mutation is critical in treatment of these tumours with recently derived small molecule ALK inhibitors. We propose increased serial sampling of tumour material from high-risk NB tumours and analysis with the new sequencing techniques. In paper II we observed that the distal part of chromosome arm 2p often is subjected to gain of an extra copy – i.e. 2p-gain. Interestingly, this region contains three genes, ALKAL2, MYCN and ALK, of strong importance for NB development. We suggest that the gain of this “cassette” of genes is beneficial to the NB tumor pathogenesis with potential to aid in therapeutical intervention. In the last study, paper IV, we analysed the high-risk 11q-deleted NB tumours. We show that 11q-deleted tumours with and without MYCN amplification present different 11q-deletion breakpoint patterns. The detailed analysis of these patterns enabled us to detect genes and chromosomal regions on 11q that may contain tumour suppressors in this severe child cancer subgroup. Furthermore, we propose DLG2 as a highly interesting 11q candidate NB gene. Conclusion - Our observation of a significant spatiotemporal variation of ALK mutations is of utmost importance in clinical practice. DLG2 stands out as a strong tumor suppressor candidate for the 11q-deleted NBs. It is important to note that the experiments we propose are expected to contribute to precision medicine.
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| 5. |
- Javanmardi, Niloufar, et al.
(författare)
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Low Frequency ALK Hotspots Mutations In Neuroblastoma Tumours Detected By Ultra-deep Sequencing: Implications For ALK Inhibitor Treatment
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The ALK tyrosine kinase receptor is oncogenically activated in neuroblastoma. Whereas numerous ALK fusion genes have been reported in different malignancies, in neuroblastoma ALK is mainly activated through point mutations. Three hotspot residues (F1174, F1245, and R1275) account for 85% of mutant ALK seen in neuroblastoma. In a cohort of 105 Swedish neuroblastoma cases of all stages, these hotspot regions were re-sequenced (> 5000X). ALK mutations were detected in 16 of 105 patients (range of variant allele fraction: 2.7-60%). Mutations at the F1174 and F1245 hotspot were observed in eleven and three cases respectively. ALK mutations were also detected at the I1171 and L1240 codons in one tumor each. No mutations were detected at R1275. Sanger sequencing could confirm ALK status for all mutated samples with variant allele fraction above 15%. Four of the samples with subclonal ALK mutation fraction below this would have gone undetected relying on Sanger sequencing only. No distinct mutation spectrum in relation to neuroblastoma tumours genomic subtypes could be detected although there was a paucity of ALK mutations among 11q-deleted tumors. As ALK mutations status opens up an excellent opportunity for application of small molecule inhibitors targeting ALK, early and sensitive detection of ALK alterations is clinically important considering its potential role in tumour progression.
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| 6. |
- Martinez-Monleon, Angela, et al.
(författare)
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Amplification of CDK4 and MDM2: a detailed study of a high-risk neuroblastoma subgroup
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- In neuroblastoma, MYCN amplification and 11q-deletion are important, although incomplete, markers of high-risk disease. It is therefore relevant to characterize additional alterations that can function as prognostic and/or predictive markers. Using SNP-microarrays, a group of neuroblastoma patients showing amplification of one or multiple 12q loci was identified. Two loci containing CDK4 and MDM2 were commonly co-amplified, although amplification of either locus in the absence of the other was observed. Pharmacological inhibition of CDK4/6 with ribociclib or abemaciclib decreased proliferation in a broad set of neuroblastoma cell lines, including CDK4/MDM2-amplified, whereas MDM2 inhibition by Nutlin-3a was only effective in p53(wild-type) cells. Combined CDK4/MDM2 targeting had an additive effect in p53(wild-type) cell lines, while no or negative additive effect was observed in p53(mutated) cells. Most 12q-amplified primary tumors were of abdominal origin, including those of intrarenal origin initially suspected of being Wilms' tumor. An atypical metastatic pattern was also observed with low degree of bone marrow involvement, favoring other sites such as the lungs. Here we present detailed biological data of an aggressive neuroblastoma subgroup hallmarked by 12q amplification and atypical clinical presentation for which our in vitro studies indicate that CDK4 and/or MDM2 inhibition also could be beneficial.
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| 7. |
- Milosevic, Jelena, et al.
(författare)
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PPM1D is a neuroblastoma oncogene and therapeutic target in childhood neural tumors
- 2020
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Majority of cancers harbor alterations of the tumor suppressor TP53. However, childhood cancers, including unfavorable neuroblastoma, often lack TP53 mutations despite frequent loss of p53 function, suggesting alternative p53 inactivating mechanisms.Here we show that p53-regulating PPM1D at chromosome 17q22.3 is linked to aggressive tumors and poor prognosis in neuroblastoma. We identified that WIP1-phosphatase encoded by PPM1D, is activated by frequent segmental 17q-gain further accumulated during clonal evolution, gene-amplifications, gene-fusions or gain-of-function somatic and germline mutations. Pharmacological and genetic manipulation established WIP1 as a druggable target in neuroblastoma. Genome-scale CRISPR-Cas9 screening demonstrated PPM1D genetic dependency in TP53 wild-type neuroblastoma cell lines, and shRNA PPM1D knockdown significantly delayed in vivo tumor formation. Establishing a transgenic mouse model overexpressing PPM1D showed that these mice develop cancers phenotypically and genetically similar to tumors arising in mice with dysfunctional p53 when subjected to low-dose irradiation. Tumors include T-cell lymphomas harboring Notch1-mutations, Pten-deletions and p53-accumulation, adenocarcinomas and PHOX2B-expressing neuroblastomas establishing PPM1D as a bona fide oncogene in wtTP53 cancer and childhood neuroblastoma. Pharmacological inhibition of WIP1 suppressed the growth of neural tumors in nude mice proposing WIP1 as a therapeutic target in neural childhood tumors.
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| 8. |
- Rasmuson, Agnes, et al.
(författare)
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Tumor Development, Growth Characteristics and Spectrum of Genetic Aberrations in the TH-MYCN Mouse Model of Neuroblastoma
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: The TH-MYCN transgenic neuroblastoma model, with targeted MYCN expression to the developing neural crest, has been used to study neuroblastoma development and evaluate novel targeted tumor therapies. Methods: We followed tumor development in 395 TH-MYCN (129X1/SvJ) mice (125 negative, 206 hemizygous and 64 homozygous mice) by abdominal palpations up to 40 weeks of age. DNA sequencing of MYCN in the original plasmid construct and mouse genomic DNA was done to verify the accuracy. Copy number analysis with Affymetrix(R) Mouse Diversity Genotyping Arrays was used to characterize acquired genetic aberrations. Results: DNA sequencing confirmed presence of human MYCN cDNA in genomic TH-MYCN DNA corresponding to the original plasmid construct. Tumor incidence and growth correlated significantly to transgene status with event-free survival for hemizygous mice at 50%, and 0% for homozygous mice. Hemizygous mice developed tumors at 5.6-19 weeks (median 9.1) and homozygous mice at 4.0-6.9 weeks (5.4). The mean treatment window, time from palpable tumor to sacrifice, for hemizygous and homozygous mice was 15 and 5.2 days, respectively. Hemizygous mice developing tumors as early as homozygous mice had a longer treatment window. Age at tumor development did not influence treatment window for hemizygous mice, whereas treatment window in homozygous mice decreased significantly with increasing age. Seven out of 10 analysed tumors had a flat DNA profile with neither segmental nor numerical chromosomal aberrations. Only three tumors from hemizygous mice showed acquired genetic features with one or more numerical aberrations. Of these, one event corresponded to gain on the mouse equivalent of human chromosome 17. Conclusion: Hemizygous and homozygous TH-MYCN mice have significantly different neuroblastoma incidence, tumor growth characteristics and treatment windows but overlap in age at tumor development making correct early genotyping essential to evaluate therapeutic interventions. Contrasting previous studies, our data show that TH-MYCN tumors have few genetic aberrations.
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| 9. |
- Schleiermacher, G., et al.
(författare)
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Emergence of New ALK Mutations at Relapse of Neuroblastoma
- 2014
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Ingår i: Journal of Clinical Oncology. - : American Society of Clinical Oncology (ASCO). - 0732-183X .- 1527-7755. ; 32:25, s. 2727-2734
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Tidskriftsartikel (refereegranskat)abstract
- Purpose In neuroblastoma, the ALK receptor tyrosine kinase is activated by point mutations. We investigated the potential role of ALK mutations in neuroblastoma clonal evolution. We analyzed ALK mutations in 54 paired diagnosis-relapse neuroblastoma samples using Sanger sequencing. When an ALK mutation was observed in one paired sample, a minor mutated component in the other sample was searched for by more than 100,000 x deep sequencing of the relevant hotspot, with a sensitivity of 0.17%. All nine ALK-mutated cases at diagnosis demonstrated the same mutation at relapse, in one case in only one of several relapse nodules. In five additional cases, the mutation seemed to be relapse specific, four of which were investigated by deep sequencing. In two cases, no mutation evidence was observed at diagnosis. In one case, the mutation was present at a subclonal level (0.798%) at diagnosis, whereas in another case, two different mutations resulting in identical amino acid changes were detected, one only at diagnosis and the other only at relapse. Further evidence of clonal evolution of ALK-mutated cells was provided by establishment of a fully ALK-mutated cell line from a primary sample with an ALK-mutated cell population at subclonal level (6.6%). In neuroblastoma, subclonal ALK mutations can be present at diagnosis with subsequent clonal expansion at relapse. Given the potential of ALK-targeted therapy, the significant spatiotemporal variation of ALK mutations is of utmost importance, highlighting the potential of deep sequencing for detection of subclonal mutations with a sensitivity 100-fold that of Sanger sequencing and the importance of serial samplings for therapeutic decisions.
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| 10. |
- Schleiermacher, Gudrun, et al.
(författare)
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Emergence of New ALK Mutations at Relapse of Neuroblastoma
- 2014
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Ingår i: Journal of Clinical Oncology. - : American Society of Clinical Oncology: JCO. - 0732-183X .- 1527-7755. ; 32:25, s. 2727-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose In neuroblastoma, the ALK receptor tyrosine kinase is activated by point mutations. We investigated the potential role of ALK mutations in neuroblastoma clonal evolution. Methods We analyzed ALK mutations in 54 paired diagnosis-relapse neuroblastoma samples using Sanger sequencing. When an ALK mutation was observed in one paired sample, a minor mutated component in the other sample was searched for by more than 100,000 x deep sequencing of the relevant hotspot, with a sensitivity of 0.17%. Results All nine ALK-mutated cases at diagnosis demonstrated the same mutation at relapse, in one case in only one of several relapse nodules. In five additional cases, the mutation seemed to be relapse specific, four of which were investigated by deep sequencing. In two cases, no mutation evidence was observed at diagnosis. In one case, the mutation was present at a subclonal level (0.798%) at diagnosis, whereas in another case, two different mutations resulting in identical amino acid changes were detected, one only at diagnosis and the other only at relapse. Further evidence of clonal evolution of ALK-mutated cells was provided by establishment of a fully ALK-mutated cell line from a primary sample with an ALK-mutated cell population at subclonal level (6.6%). Conclusion In neuroblastoma, subclonal ALK mutations can be present at diagnosis with subsequent clonal expansion at relapse. Given the potential of ALK-targeted therapy, the significant spatiotemporal variation of ALK mutations is of utmost importance, highlighting the potential of deep sequencing for detection of subclonal mutations with a sensitivity 100-fold that of Sanger sequencing and the importance of serial samplings for therapeutic decisions.
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