| 1. |
- Danielsson, Anna, 1973, et al.
(författare)
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MethPed: a DNA methylation classifier tool for the identification of pediatric brain tumor subtypes
- 2015
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Ingår i: Clinical Epigenetics. - : Springer Science and Business Media LLC. - 1868-7083 .- 1868-7075. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Classification of pediatric tumors into biologically defined subtypes is challenging, and multifaceted approaches are needed. For this aim, we developed a diagnostic classifier based on DNA methylation profiles. Results: Methylation data generated by the Illumina Infinium HumanMethylation 450 BeadChip arrays were downloaded from the Gene Expression Omnibus (n = 472). Using the data, we built MethPed, which is a multiclass random forest algorithm, based on DNA methylation profiles from nine subgroups of pediatric brain tumors. DNA from 18 regional samples was used to validate MethPed. MethPed was additionally applied to a set of 28 publically available tumors with the heterogeneous diagnosis PNET. MethPed could successfully separate individual histology tumor types at a very high accuracy (kappa = 0.98). Analysis of a regional cohort demonstrated the clinical benefit of MethPed, as confirmation of diagnosis of tumors with clear histology but also identified possible differential diagnoses in tumors with complicated and mixed type morphology. Conclusions: We demonstrate the utility of methylation profiling of pediatric brain tumors and offer MethPed as an easy-to-use toolbox that allows researchers and clinical diagnosticians to test single samples as well as large cohorts for subclass prediction of pediatric brain tumors. This will immediately aid clinical practice and importantly increase our molecular knowledge of these tumors for further therapeutic development.
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| 2. |
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| 3. |
- Wenger, Anna, 1990, et al.
(författare)
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Stem cell cultures derived from pediatric brain tumors accurately model the originating tumors.
- 2017
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 8, s. 18626-18639
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Tidskriftsartikel (refereegranskat)abstract
- Brain tumors are the leading cause of cancer-related death in children but high-grade gliomas in children and adolescents have remained a relatively under-investigated disease despite this. A better understanding of the cellular and molecular pathogenesis of the diseases is required in order to improve the outcome for these children. In vitro-cultured primary tumor cells from patients are indispensable tools for this purpose by enabling functional analyses and development of new therapies. However, relevant well-characterized in vitro cultures from pediatric gliomas cultured under serum-free conditions have been lacking. We have therefore established patient-derived in vitro cultures and performed thorough characterization of the cells using large-scale analyses of DNA methylation, copy-number alterations and investigated their stability during prolonged time in culture. We show that the cells were stable during prolonged culture in serum-free stem cell media without apparent alterations in morphology or growth rate. The cells were proliferative, positive for stem cell markers, able to respond to differentiation cues and initiated tumors in zebrafish and mice suggesting that the cells are cancer stem cells or progenitor cells. The cells accurately mirrored the tumor they were derived from in terms of methylation pattern, copy number alterations and DNA mutations. These unique primary in vitro cultures can thus be used as a relevant and robust model system for functional studies on pediatric brain tumors.
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| 4. |
- Campbell, Brittany B., et al.
(författare)
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Comprehensive Analysis of Hypermutation in Human Cancer
- 2017
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 171:5
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Elsevier Inc. We present an extensive assessment of mutation burden through sequencing analysis of > 81,000 tumors from pediatric and adult patients, including tumors with hypermutation caused by chemotherapy, carcinogens, or germline alterations. Hypermutation was detected in tumor types not previously associated with high mutation burden. Replication repair deficiency was a major contributing factor. We uncovered new driver mutations in the replication-repair-associated DNA polymerases and a distinct impact of microsatellite instability and replication repair deficiency on the scale of mutation load. Unbiased clustering, based on mutational context, revealed clinically relevant subgroups regardless of the tumors' tissue of origin, highlighting similarities in evolutionary dynamics leading to hypermutation. Mutagens, such as UV light, were implicated in unexpected cancers, including sarcomas and lung tumors. The order of mutational signatures identified previous treatment and germline replication repair deficiency, which improved management of patients and families. These data will inform tumor classification, genetic testing, and clinical trial design. A large-scale analysis of hypermutation in human cancers provides insights into tumor evolution dynamics and identifies clinically actionable mutation signatures.
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| 5. |
- Larsson, Susanna, et al.
(författare)
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Cell line-based xenograft mouse model of paediatric glioma stem cells mirrors the clinical course of the patient
- 2018
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 39:10, s. 1304-1309
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Tidskriftsartikel (refereegranskat)abstract
- The leading cause of cancer-related mortality among children is brain tumour, and glioblastoma multiforme (GBM) has the worst prognosis. New treatments are urgently needed, but with few cases and clinical trials in children, pre-clinical models such as patient-derived tumour xenografts (PDTX) are important. To generate these, tumour tissue is transplanted into mice, but this yields highly variable results and requires serial passaging in mice, which is time-consuming and expensive. We therefore aimed to establish a cell line-based orthotopic mouse model representative of the patient tumour. Glioma stem cell (GSC) lines derived from paediatric GBM were orthotopically transplanted into immunodeficient mice. Overall survival data were collected and histological analysis of the resulting neoplasias was performed. Genome-wide DNA methylation arrays were used for methylation and copy-number alterations (CNA) profiling. All GSC lines initiated tumours on transplantation and the survival of the mice correlated well with the survival of the patients. Xenograft tumours presented histological hallmarks of GBM, and were also classified as GBM by methylation profiling. Each xenograft tumour clustered together with its respective injected GSC line and patient tumour based on the methylation data. We have established a robust and reproducible cell line-based xenograft paediatric GBM model. The xenograft tumours accurately reflected the patient tumours and mirrored the clinical course of the patient. This model can therefore be used to assess patient response in pre-clinical studies.
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| 6. |
- Meeths, Marie, et al.
(författare)
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Incidence and clinical presentation of primary hemophagocytic lymphohistiocytosis in Sweden.
- 2015
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Ingår i: Pediatric blood & cancer. - : Wiley. - 1545-5017 .- 1545-5009. ; 62:2, s. 346-352
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Tidskriftsartikel (refereegranskat)abstract
- Primary hemophagocytic lymphohistiocytosis (HLH) represents a group of inherited hyperinflammatory immunodeficiencies, including familial HLH (FHL), Griscelli syndrome type 2 (GS2), and X-linked lymphoproliferative syndrome (XLP). We previously reported an annual incidence of suspected primary HLH in Sweden 1971-1986 of 0.12 per 100,000 children. Here, we determined if the incidence had increased with concomitant awareness.
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| 7. |
- Sabel, Magnus, 1966, et al.
(författare)
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Active video gaming improves body coordination in survivors of childhood brain tumours.
- 2016
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Ingår i: Disability and rehabilitation. - : Informa UK Limited. - 1464-5165 .- 0963-8288. ; 38:21, s. 2073-2084
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Tidskriftsartikel (refereegranskat)abstract
- Purpose We investigated whether active video gaming (AVG) could bring about regular, enjoyable, physical exercise in children treated for brain tumours, what level of physical activity could be reached and if the children's physical functioning improved. Methods Thirteen children, aged 7-17 years, were randomised to either AVG or waiting-list. After 10-12 weeks they crossed-over. Weekly Internet coaching sessions were used to sustain motivation and evaluate enjoyment. Energy expenditure (EE) levels were measured as Metabolic Equivalent of Task (MET), using a multisensory activity monitor. Single-blinded assessments of physical functioning were done, using the Bruininks-Osteretsky Test of Motor Performance, second edition, evaluating participants before and after the intervention period, as well as comparing the randomisation groups after the first period. Results All patients completed the study. AVG sessions (mean duration 47minutes) were performed on 72% of all days. Mean EE level during AVG sessions was 3.0 MET, corresponding to moderate physical activity. The Body Coordination score improved by 15% (p=0.021) over the intervention period. Conclusions In this group of childhood brain tumour survivors, home-based AVG, supported by a coach, was a feasible, enjoyable and moderately intense form of exercise that improved Body Coordination. Implications for Rehabilitation Childhood brain tumour survivors frequently have cognitive problems, inferior physical functioning and are less physically active compared to their healthy peers. Active video gaming (AVG), supported by Internet coaching, is a feasible home-based intervention in children treated for brain tumours, promoting enjoyable, regular physical exercise of moderate intensity. In this pilot study, AVG with Nintendo Wii improved Body Coordination.
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| 8. |
- Sabel, Magnus, 1966, et al.
(författare)
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Effects of physically active video gaming on cognition and activities of daily living in childhood brain tumor survivors: a randomized pilot study
- 2017
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Ingår i: Neuro Oncology Practice. - : Oxford University Press (OUP). - 2054-2577 .- 2054-2585. ; 4:2, s. 98-110
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Tidskriftsartikel (refereegranskat)abstract
- Background. Physical activity can enhance cognitive functions in both animals and humans. We hypothesized that physically active video gaming could: i) improve cognitive functions and ii) improve the execution of activities of daily living among survivors of childhood brain tumors.Methods. Children 7 to 17 years old who completed treatment, including radiotherapy, for a brain tumor 1 to 5 years earlier were randomized to either intervention or waiting list. After 10 to 12 weeks the groups crossed over. The intervention consisted of active video gaming, using a motion-controlled video console (Nintendo Wii), for a minimum of 30 minutes a day, 5 days a week and weekly Internet-based coaching sessions. Evaluations before and after each period included tests of the execution of activities of daily living, using the Assessment of Motor and Process Skills (AMPS) and cognitive tests. Test scores before and after the intervention were compared. A parallel group comparison was performed as a sensitivity analysis.Results. All 13 children enrolled completed the program. Compared to baseline, the motor (P= .012) and process (P=.002) parts of AMPS improved significantly after active video gaming. In the parallel group analysis the improvement in the process part of AMPS remained statistically significant (P= .029), but not the change in AMPS motor score (P= .059). No significant change was found in cognitive tests although there were trends for improvement in sustained attention (P = .090) and selective attention (P = .078).Conclusion. In this pilot study, active video gaming used as a home-based intervention for childhood brain tumor survivors improved motor and process skills in activities of daily living.
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| 9. |
- Sabel, Magnus, 1966, et al.
(författare)
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Hypothermia after cranial irradiation protects neural progenitor cells in the subventricular zone but not in the hippocampus.
- 2017
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Ingår i: International journal of radiation biology. - : Informa UK Limited. - 1362-3095 .- 0955-3002. ; 93:8, s. 771-783
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Tidskriftsartikel (refereegranskat)abstract
- To explore if hypothermia can reduce the harmful effects of ionizing radiation on the neurogenic regions of the brain in young rats.Postnatal day 9 rats were randomized into two treatment groups, hypo- and normothermia, or a control group. Treatment groups were placed in chambers submerged in temperature-controlled water baths (30˚C and 36˚C) for 8h, after receiving a single fraction of 8Gy to the left hemisphere. Seven days post-irradiation, we measured the sizes of the subventricular zone (SVZ) and the granule cell layer (GCL) of the hippocampus, and counted the number of proliferating (phospho-histone H3+) cells and microglia (Iba1+ cells).Irradiation caused a 53% reduction in SVZ size in the normothermia group compared to controls, as well as a reduction of proliferating cell numbers by >50%. These effects were abrogated in the hypothermia group. Irradiation reduced the number of microglia in both treatment groups, but resulted in a lower cell density of Iba1+ cells in the SVZs of the hypothermia group. In the GCL, irradiation decreased both GCL size and the proliferating cell numbers, but with no difference between the treatment groups. The number of microglia in the GCL did not change.Hypothermia immediately after irradiation protects the SVZ and its proliferative cell population but the GCL is not protected, one week post-irradiation.
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| 10. |
- Sabel, Magnus, 1966, et al.
(författare)
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Relapse patterns and outcome after relapse in standard risk medulloblastoma: a report from the HIT-SIOP-PNET4 study
- 2016
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Ingår i: Journal of Neuro-Oncology. - : Springer Science and Business Media LLC. - 0167-594X .- 1573-7373. ; 129:3, s. 515-524
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Tidskriftsartikel (refereegranskat)abstract
- © 2016 The Author(s)The HIT-SIOP-PNET4 randomised trial for standard risk medulloblastoma (MB) (2001–2006) included 338 patients and compared hyperfractionated and conventional radiotherapy. We here report the long-term outcome after a median follow up of 7.8 years, including detailed information on relapse and the treatment of relapse. Data were extracted from the HIT Group Relapsed MB database and by way of a specific case report form. The event-free and overall (OS) survival at 10 years were 76 ± 2 % and 78 ± 2 % respectively with no significant difference between the treatment arms. Seventy-two relapses and three second malignant neoplasms were reported. Thirteen relapses (18 %) were isolated local relapses in the posterior fossa (PF) and 59 (82 %) were craniospinal, metastatic relapses (isolated or multiple) with or without concurrent PF disease. Isolated PF relapse vs all other relapses occurred at mean/median of 38/35 and 28/26 months respectively (p = 0.24). Late relapse, i.e. >5 years from diagnosis, occurred in six patients (8 %). Relapse treatment consisted of combinations of surgery (25 %), focal radiotherapy (RT 22 %), high dose chemotherapy with stem cell rescue (HDSCR 21 %) and conventional chemotherapy (90 %). OS at 5 years after relapse was 6.0 ± 4 %. In multivariate analysis; isolated relapse in PF, and surgery were significantly associated with prolonged survival whereas RT and HDSCR were not. Survival after relapse was not related to biological factors and was very poor despite several patients receiving intensive treatments. Exploration of new drugs is warranted, preferably based on tumour biology from biopsy of the relapsed tumour.
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