| 1. |
|
|
| 2. |
- Schepke, Elizabeth
(författare)
-
Brain tumors in children - National population-based studies on classification, diagnostics and long-term follow-up
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although the prognosis for pediatric tumors of the central nervous system (CNS) has improved over time it is urgent to reduce mortality and improve long-term quality of life for survivors. With this aim, the first step is to identify the correct diagnosis in order to choose the right therapy and avoid unnecessary treatment. Establishing a correct diagnosis can be challenging and genome-wide DNA methylation profiling has evolved as a valuable tool in the diagnostics of childhood CNS tumors. The aim of this thesis was 1) to provide comprehensive data on children diagnosed with a CNS tumor in Sweden between 1984-2021, and 2) to evaluate the added value of performing DNA methylation profiling in the standard diagnostics of pediatric CNS tumors in Sweden. In Paper I we found a stable incidence of childhood CNS tumors during the study period of almost 40 years. The distribution of tumor diagnoses was relatively comparable to that reported from other countries. Overall survival for children diagnosed with a CNS tumor has improved over time but for several tumor types the long-term survival rates continued to decrease. In paper II we determined that integrating DNA methylation profiling into real time diagnostics of pediatric CNS tumors improves diagnostics and provides molecular information that has shown to be essential for choosing the optimal treatment. We demonstrated that methylation profiling has a role in the classification of all types of CNS tumors, also those with a lower tumor cell content. In paper III we re-classified tumors formerly diagnosed as CNS primitive neuroectodermal tumor (PNET). We confirmed the heterogeneity of these tumors and concluded that DNA methylation has a pivotal role in the diagnostics of rare childhood embryonal tumors. The survival rates for the re-classified tumor types were in line with other studies. All patients with CNS NB-FOXR2 had received craniospinal irradiation and the prognosis was excellent.
|
|
| 3. |
- Schepke, Elizabeth, et al.
(författare)
-
DNA methylation profiling improves routine diagnosis of paediatric central nervous system tumours: A prospective population-based study
- 2022
-
Ingår i: Neuropathology and Applied Neurobiology. - : Wiley. - 0305-1846 .- 1365-2990. ; 48:6
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: Paediatric brain tumours are rare, and establishing a precise diagnosis can be challenging. Analysis of DNA methylation profiles has been shown to be a reliable method to classify central nervous system (CNS) tumours with high accuracy. We aimed to prospectively analyse CNS tumours diagnosed in Sweden, to assess the clinical impact of adding DNA methylation-based classification to standard paediatric brain tumour diagnostics in an unselected cohort. Methods: All CNS tumours diagnosed in children (0-18 years) during 2017-2020 were eligible for inclusion provided sufficient tumour material was available. Tumours were analysed using genome-wide DNA methylation profiling and classified by the MNP brain tumour classifier. The initial histopathological diagnosis was compared with the DNA methylation-based classification. For incongruent results, a blinded re-evaluation was performed by an experienced neuropathologist. Results: Two hundred forty tumours with a histopathology-based diagnosis were profiled. A high-confidence methylation score of 0.84 or more was reached in 78% of the cases. In 69%, the histopathological diagnosis was confirmed, and for some of these also refined, 6% were incongruent, and the re-evaluation favoured the methylation-based classification. In the remaining 3% of cases, the methylation class was non-contributory. The change in diagnosis would have had a direct impact on the clinical management in 5% of all patients. Conclusions: Integrating DNA methylation-based tumour classification into routine clinical analysis improves diagnostics and provides molecular information that is important for treatment decisions. The results from methylation profiling should be interpreted in the context of clinical and histopathological information.
|
|
| 4. |
- Schepke, Elizabeth, et al.
(författare)
-
Effects of the growth pattern of medulloblastoma on short-term neurological impairments after surgery: results from the prospective multicenter HIT-SIOP PNET 4 study
- 2020
-
Ingår i: Journal of Neurosurgery-Pediatrics. - 1933-0707. ; 25:4, s. 425-433
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE Extensive resection of a tumor in the posterior fossa in children is associated with the risk of neurological deficits. The objective of this study was to prospectively evaluate the short-term neurological morbidity in children after medulloblastoma surgery and relate this to the tumor's growth pattern and to the extent of resection. METHODS In 160 patients taking part in the HIT-STOP PNET 4 (Hyperfractionated Versus Conventionally Fractionated Radiotherapy in Standard Risk Medulloblastoma) trial, neurosurgeons prospectively responded to questions concerning the growth pattern of the tumor they had resected. The extent of resection (gross, near, or subtotal) was evaluated using MRI. The patients' neurological status before resection and around 30 days after resection was recorded. RESULTS Invasive tumor growth, defined as local invasion in the brain or meninges, cranial nerve, or major vessel, was reported in 58% of the patients. After surgery almost 70% of all patients were affected by one or several neurological impairments (e.g., impaired vision, impaired extraocular movements, and ataxia). However, this figure was very similar to the preoperative findings. Invasive tumor growth implied a significantly higher number of impairments after surgery (p = 0.03) and greater deterioration regarding extraocular movements (p = 0.012), facial weakness (p = 0.048), and ataxia in the arms (p = 0.014) and trunk (p = 0.025) compared with noninvasive tumor growth. This deterioration was not dependent on the extent of resection performed. Progression-free survival (PFS) at 5 years was 80% +/- 4% and 76% +/- 5% for patients with invasive and noninvasive tumor growth, respectively, with no difference in the 5-year PFS for extent of resection. CONCLUSIONS Preoperative neurological impairments and invasive tumor growth were strong predictors of deterioration in short-term neurological outcome after medulloblastoma neurosurgery, whereas the extent of resection was not . Neither tumor invasiveness nor extent of resection influenced PFS. These findings support the continuation of maximal safe resection in medulloblastoma surgery where functional risks are not taken in areas with tumor invasion.
|
|
| 5. |
- Schepke, Elizabeth, et al.
(författare)
-
Supratentorial CNS-PNETs in children; a Swedish population-based study with molecular re-evaluation and long-term follow-up
- 2023
-
Ingår i: Clinical Epigenetics. - : Springer Science and Business Media LLC. - 1868-7075 .- 1868-7083. ; 15:1
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundMolecular analyses have shown that tumours diagnosed as supratentorial primitive neuro-ectodermal tumours of the central nervous system (CNS-PNETs) in the past represent a heterogenous group of rare childhood tumours including high-grade gliomas (HGG), ependymomas, atypical teratoid/rhabdoid tumours (AT/RT), CNS neuroblastoma with forkhead box R2 (FOXR2) activation and embryonal tumour with multi-layered rosettes (ETMR). All these tumour types are rare and long-term clinical follow-up data are sparse. We retrospectively re-evaluated all children (0-18 years old) diagnosed with a CNS-PNET in Sweden during 1984-2015 and collected clinical data.MethodsIn total, 88 supratentorial CNS-PNETs were identified in the Swedish Childhood Cancer Registry and from these formalin-fixed paraffin-embedded tumour material was available for 71 patients. These tumours were histopathologically re-evaluated and, in addition, analysed using genome-wide DNA methylation profiling and classified by the MNP brain tumour classifier.ResultsThe most frequent tumour types, after histopathological re-evaluation, were HGG (35%) followed by AT/RT (11%), CNS NB-FOXR2 (10%) and ETMR (8%). DNA methylation profiling could further divide the tumours into specific subtypes and with a high accuracy classify these rare embryonal tumours. The 5 and 10-year overall survival (OS) for the whole CNS-PNET cohort was 45% +/- 12% and 42% +/- 12%, respectively. However, the different groups of tumour types identified after re-evaluation displayed very variable survival patterns, with a poor outcome for HGG and ETMR patients with 5-year OS 20% +/- 16% and 33% +/- 35%, respectively. On the contrary, high PFS and OS was observed for patients with CNS NB-FOXR2 (5-year 100% for both). Survival rates remained stable even after 15-years of follow-up.ConclusionsOur findings demonstrate, in a national based setting, the molecular heterogeneity of these tumours and show that DNA methylation profiling of these tumours provides an indispensable tool in distinguishing these rare tumours. Long-term follow-up data confirms previous findings with a favourable outcome for CNS NB-FOXR2 tumours and poor chances of survival for ETMR and HGG.
|
|
| 6. |
- Wenger, Anna, 1990, et al.
(författare)
-
DNA methylation alterations across time and space in paediatric brain tumours
- 2022
-
Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- DNA methylation is increasingly used for tumour classification and has expanded upon the > 100 currently known brain tumour entities. A correct diagnosis is the basis for suitable treatment for patients with brain tumours, which is the leading cause of cancer-related death in children. DNA methylation profiling is required for diagnosis of certain tumours, and used clinically for paediatric brain tumours in several countries. We therefore evaluated if the methylation-based classification is robust in different locations of the same tumour, and determined how the methylation pattern changed over time to relapse. We sampled 3-7 spatially separated biopsies per patient, and collected samples from paired primary and relapse brain tumours from children. Altogether, 121 samples from 46 paediatric patients with brain tumours were profiled with EPIC methylation arrays. The methylation-based classification was mainly homogeneous for all included tumour types that were successfully classified, which is promising for clinical diagnostics. There were indications of multiple subclasses within tumours and switches in the relapse setting, but not confirmed as the classification scores were below the threshold. Site-specific methylation alterations did occur within the tumours and varied significantly between tumour types for the temporal samples, and as a trend in spatial samples. More alterations were present in high-grade tumours compared to low-grade, and significantly more alterations with longer relapse times. The alterations in the spatial and temporal samples were significantly depleted in CpG islands, exons and transcription start sites, while enriched in OpenSea and regions not affiliated with a gene, suggesting a random location of the alterations in less conserved regions. In conclusion, more DNA methylation changes accumulated over time and more alterations occurred in high-grade tumours. The alterations mainly occurred in regions without gene affiliation, and did not affect the methylation-based classification, which largely remained homogeneous in paediatric brain tumours.
|
|
| 7. |
- Wenger, Anna, 1990, et al.
(författare)
-
Stem cell cultures derived from pediatric brain tumors accurately model the originating tumors.
- 2017
-
Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 8, s. 18626-18639
-
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.
|
|
