scholarly journals Mechanisms of telomere maintenance in pediatric brain tumors: Promising targets for therapy – A narrative review

Glioma ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 105
Author(s):  
Felice Giangaspero ◽  
Simone Minasi ◽  
Francesca Gianno ◽  
Hiba Alzoubi ◽  
Manila Antonelli ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Pediatric Brain Tumors ◽  
Narrative Review ◽  
Telomere Maintenance ◽  
Pediatric Brain

scholarly journals Changes in the Expression of Pre-Replicative Complex Genes in hTERT and ALT Pediatric Brain Tumors

Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1028 ◽  
Author(s):  
Aurora Irene Idilli ◽  
Francesca Pagani ◽  
Emanuela Kerschbamer ◽  
Francesco Berardinelli ◽  
Manuel Bernabé ◽  
...  
Keyword(s):  
Gene Expression ◽  
Brain Tumors ◽  
Cancer Cells ◽  
Pediatric Brain Tumors ◽  
Telomere Maintenance ◽  
Telomeric Dna ◽  
Maintenance Mechanism ◽  
Alternative Lengthening ◽  
Differential Gene ◽  
Pediatric Brain

Background: The up-regulation of a telomere maintenance mechanism (TMM) is a common feature of cancer cells and a hallmark of cancer. Routine methods for detecting TMMs in tumor samples are still missing, whereas telomerase targeting treatments are becoming available. In paediatric cancers, alternative lengthening of telomeres (ALT) is found in a subset of sarcomas and malignant brain tumors. ALT is a non-canonical mechanism of telomere maintenance developed by cancer cells with no-functional telomerase. Methods: To identify drivers and/or markers of ALT, we performed a differential gene expression analysis between two zebrafish models of juvenile brain tumors, that differ only for the telomere maintenance mechanism adopted by tumor cells: one is ALT while the other is telomerase-dependent. Results: Comparative analysis of gene expression identified five genes of the pre-replicative complex, ORC4, ORC6, MCM2, CDC45 and RPA3 as upregulated in ALT. We searched for a correlation between telomerase levels and expression of the pre-replicative complex genes in a cohort of paediatric brain cancers and identified a counter-correlation between telomerase expression and the genes of the pre-replicative complex. Moreover, the analysis of ALT markers in a group of 20 patients confirmed the association between ALT and increased RPA and decreased H3K9me3 localization at telomeres. Conclusions: Our study suggests that telomere maintenance mechanisms may act as a driver of telomeric DNA replication and chromatin status in brain cancers and identifies markers of ALT that could be exploited for precise prognostic and therapeutic purposes.

scholarly journals A pediatric brain tumor atlas of genes deregulated by somatic genomic rearrangement

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yiqun Zhang ◽  
Fengju Chen ◽  
Lawrence A. Donehower ◽  
Michael E. Scheurer ◽  
Chad J. Creighton
Keyword(s):  
Brain Tumor ◽  
Brain Tumors ◽  
Tyrosine Kinases ◽  
Pediatric Brain Tumor ◽  
Pediatric Brain Tumors ◽  
Altered Expression ◽  
Critical Pathways ◽  
Cis Regulation ◽  
Or Gene ◽  
Pediatric Brain

AbstractThe global impact of somatic structural variants (SSVs) on gene expression in pediatric brain tumors has not been thoroughly characterised. Here, using whole-genome and RNA sequencing from 854 tumors of more than 30 different types from the Children’s Brain Tumor Tissue Consortium, we report the altered expression of hundreds of genes in association with the presence of nearby SSV breakpoints. SSV-mediated expression changes involve gene fusions, altered cis-regulation, or gene disruption. SSVs considerably extend the numbers of patients with tumors somatically altered for critical pathways, including receptor tyrosine kinases (KRAS, MET, EGFR, NF1), Rb pathway (CDK4), TERT, MYC family (MYC, MYCN, MYB), and HIPPO (NF2). Compared to initial tumors, progressive or recurrent tumors involve a distinct set of SSV-gene associations. High overall SSV burden associates with TP53 mutations, histone H3.3 gene H3F3C mutations, and the transcription of DNA damage response genes. Compared to adult cancers, pediatric brain tumors would involve a different set of genes with SSV-altered cis-regulation. Our comprehensive and pan-histology genomic analyses reveal SSVs to play a major role in shaping the transcriptome of pediatric brain tumors.

scholarly journals RONC-19. TWO CASES OF RE-IRRADIATION FOR LATE RECURRENT OR RADIATION-INDUCED TUMOR AFTER RADIATION THERAPY FOR PEDIATRIC BRAIN TUMORS

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii459-iii459
Author(s):  
Takashi Mori ◽  
Shigeru Yamaguchi ◽  
Rikiya Onimaru ◽  
Takayuki Hashimoto ◽  
Hidefumi Aoyama
Keyword(s):  
Radiation Therapy ◽  
Brain Tumors ◽  
Tumor Resection ◽  
Intensity Modulated Radiation Therapy ◽  
Late Recurrence ◽  
Pediatric Brain Tumors ◽  
Suprasellar Region ◽  
Radiation Induced ◽  
Pediatric Brain

Abstract BACKGROUND As the outcome of pediatric brain tumors improves, late recurrence and radiation-induced tumor cases are more likely to occur, and the number of cases requiring re-irradiation is expected to increase. Here we report two cases performed intracranial re-irradiation after radiotherapy for pediatric brain tumors. CASE 1: 21-year-old male. He was diagnosed with craniopharyngioma at eight years old and underwent a tumor resection. At 10 years old, the local recurrence of suprasellar region was treated with 50.4 Gy/28 fr of stereotactic radiotherapy (SRT). After that, other recurrent lesions appeared in the left cerebellopontine angle, and he received surgery three times. The tumor was gross totally resected and re-irradiation with 40 Gy/20 fr of SRT was performed. We have found no recurrence or late effects during the one year follow-up. CASE 2: 15-year-old female. At three years old, she received 18 Gy/10 fr of craniospinal irradiation and 36 Gy/20 fr of boost to the posterior fossa as postoperative irradiation for anaplastic ependymoma and cured. However, a anaplastic meningioma appeared on the left side of the skull base at the age of 15, and 50 Gy/25 fr of postoperative intensity-modulated radiation therapy was performed. Two years later, another meningioma developed in the right cerebellar tent, and 54 Gy/27 fr of SRT was performed. Thirty-three months after re-irradiation, MRI showed a slight increase of the lesion, but no late toxicities are observed. CONCLUSION The follow-up periods are short, however intracranial re-irradiation after radiotherapy for pediatric brain tumors were feasible and effective.

scholarly journals Ras, TrkB, and ShcA Protein Expression Patterns in Pediatric Brain Tumors

2021 ◽  
Vol 10 (10) ◽  
pp. 2219
Author(s):  
Monika Prill ◽  
Agnieszka Karkucinska-Wieckowska ◽  
Magdalena Lebiedzinska-Arciszewska ◽  
Giampaolo Morciano ◽  
Agata Charzynska ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Expression Patterns ◽  
Pediatric Brain Tumors ◽  
Astrocytic Tumors ◽  
Embryonal Tumors ◽  
Altered Expression ◽  
Malignancy Grade ◽  
Oligodendroglial Tumors ◽  
Different Types ◽  
Pediatric Brain

Numerous papers have reported altered expression patterns of Ras and/or ShcA proteins in different types of cancers. Their level can be potentially associated with oncogenic processes. We analyzed samples of pediatric brain tumors reflecting different groups such as choroid plexus tumors, diffuse astrocytic and oligodendroglial tumors, embryonal tumors, ependymal tumors, and other astrocytic tumors as well as tumor malignancy grade, in order to characterize the expression profile of Ras, TrkB, and three isoforms of ShcA, namely, p66Shc, p52Shc, and p46Shc proteins. The main aim of our study was to evaluate the potential correlation between the type of pediatric brain tumors, tumor malignancy grade, and the expression patterns of the investigated proteins.

scholarly journals DIPG-60. PILOT STUDY OF CIRCULATING TUMOR CELLS IN PEDIATRIC HIGH GRADE BRAIN TUMORS

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii299-iii299
Author(s):  
Wafik Zaky ◽  
Long Dao ◽  
Dristhi Ragoonanan ◽  
Izhar Bath ◽  
Sofia Yi ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Brain Tumors ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Pediatric Brain Tumor ◽  
Pediatric Brain Tumors ◽  
Disease Assessment ◽  
Liquid Biopsies ◽  
Capture Method ◽  
Pediatric Brain

Abstract BACKGROUND Despite its increasing use, circulating tumor cells (CTCs) have not been studied in pediatric brain tumors. METHODS Cell surface vimentin (CSV) is a marker for CTC detection. We developed an automated CSV-based CTC capture method for pediatric brain tumor using the Abnova Cytoquest platform. PBMCs isolated from blood samples from 52 brain tumor patients were processed to isolate CSV+ CTCs. Captured cells were then stained for CSV and CD45 and scanned to determine the number of CTCs. DIPG samples were additionally examined for H3K27M expression on CSV+ cells. Long term cancer survivors were used as a control cohort. RESULTS 86.4% of all the samples exhibited between 1–13 CSV+ CTCs, with a median of 2 CSV+ CTCs per sample. Using a value of ≥ 1 CTC as a positive result, the sensitivity and specificity of this test was 83.05% and 60.0% respectively. 19 DIPG samples were analyzed and 70% (13 samples) were positive for 1–5 CTCs. Five of these 7 positive CSV+ CTCs DIPG samples were also positive for H3K27M mutations by immunohistochemistry (71%). Mean survival in days for the CTC positive and negative DIPG samples were 114 and 211 days, respectively (p= 0.13). CONCLUSION This is the first study of CTCs in pediatric CNS tumors using an automated approach. Patients with brain tumors can exhibit CSV+ CTCs within peripheral blood. The use of specific molecular markers such as H3K27M can improve the diagnostic capability of liquid biopsies and may enable future disease assessment for personalized therapy.

scholarly journals EXTH-16. TREATMENT OF THREE DIFFERENT BRAF-V600E POSITIVE BRAIN TUMORS WITH VEMURAFENIB AND DABRAFENIB/TRAMETINIB: A CASE SERIES

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii90-ii90
Author(s):  
Nikita Dhir ◽  
Sheila Chandrahas ◽  
Chibuzo O’Suoji ◽  
Mohamad Al-Rahawan
Keyword(s):  
Targeted Therapy ◽  
Brain Tumors ◽  
Tumor Regression ◽  
Case Series ◽  
Pediatric Brain Tumors ◽  
Braf V600e ◽  
Cns Tumors ◽  
Braf Inhibitors ◽  
Pediatric Brain ◽  
Pediatric Cns Tumors

Abstract BACKGROUND The BRAF-V600E gene is a protein kinase involved in regulation of the mitogen activated protein kinase pathway (MAPK/MEK) and downstream extracellular receptor kinase (ERK). The BRAF-V600E mutation has a significant role in the progression of pediatric brain tumors. 85% of pediatric CNS tumors express the BRAF mutation. Thus, BRAF targeted therapy in pediatric CNS malignancies has potential to become the standard of care for tumors expressing this mutation. OBJECTIVE Current pediatric CNS brain tumor treatment focuses on chemotherapy and radiation, causing significant toxic side effects for patients. The significance of this case series lies in relaying our experience using targeted therapy in BRAF-V600E positive CNS pediatric brain tumors. METHODS We followed the disease course, progression, and treatment of three pediatric patients with three different CNS tumors. Each of these individuals was treated with surgical resection, chemotherapy, and/or radiation as per standard protocol. When that modality failed to reduce tumor progression, we found that each of their different tumors was BRAF-V600E positive and they were all started on targeted therapy. DISCUSSION Vemurafenib, Dabrafenib, and Trametinib are BRAF-V600E/MEK inhibitors that were initially used to treat melanomas. However, more research has shown that various pediatric CNS tumors are BRAF-V600 positive. Therapy with these BRAF inhibitors has been shown to slow tumor progression, but toxicity can be severe. This case series shows one patient with successful tumor regression, one patient with prolonged disease stabilization, and one patient with initial response but subsequent progression and ultimate death. It has been shown that using BRAF inhibitors in lower grade CNS tumors are more effective than higher grade CNS tumors. CONCLUSION The success of Vemurafenib and Dabrafenib/Trametinib in causing pediatric CNS tumor regression is promising, but further studies are needed to solidify their role in pediatric CNS cancers.

Sign in / Sign up

Export Citation Format

Share Document