Tumor mutational burden and driver mutations: Characterizing the genomic landscape of pediatric brain tumors

2020 ◽  
Vol 67 (7) ◽  
Author(s):  
Roshal R. Patel ◽  
Shakti H. Ramkissoon ◽  
Jeffrey Ross ◽  
Lauren Weintraub
2018 ◽  
Vol 20 (suppl_2) ◽  
pp. i181-i182
Author(s):  
Roshal Patel ◽  
Katharine Halligan ◽  
Shakti Ramkissoon ◽  
Jeffrey Ross ◽  
Lauren Weintraub

2017 ◽  
Vol 21 (4) ◽  
pp. 380-388 ◽  
Author(s):  
Bonnie L Cole ◽  
Colin C Pritchard ◽  
Maia Anderson ◽  
Sarah ES Leary

Pediatric brain tumors cause more deaths than any other childhood malignancy, and the identification of potentially actionable genomic alterations in this rare heterogeneous group of tumors may improve treatment and outcome. The genetic landscape of common posterior fossa tumors has been described in the past several years, yet the classification of malignant pediatric supratentorial tumors remains controversial. Next-generation sequencing (NGS) is a promising tool to evaluate multiple genes concurrently. The clinical utility of NGS has not been proven in pediatric brain tumors. We identified patients diagnosed with high-grade supratentorial pediatric brain tumors resected between 2008 and 2012 at our institution. DNA from 12 formalin-fixed paraffin-embedded tumor samples from 9 patients was analyzed, including 3 paired samples from diagnosis and relapse. A panel of 194 cancer-related genes was sequenced using targeted next-generation deep sequencing. Genetic findings were correlated with histology, immunohistochemistry, treatment, and survival. We found one or more pathologic genetic change (mutation, amplification, or deletion) in 8 of 9 (89%) of patients studied. Epidermal Growth Factor Receptor ( EGFR) mutations were found in 3 patients, 2 of which had an exon 20 insertion not previously described in pediatric malignancy. Additional genetic changes were found in EGFR and Platelet-Derived Growth Factor Receptor Alpha ( PDGFRA) at relapse not present in the initial samples. Familial cancer predisposition syndromes were suggested by mutations found in 3 genes in 4 patients, including TP53, MSH2, and CHEK2. Seven of 9 patients in this study died of their disease. In summary, targeted deep sequencing may be used in rare pediatric brain tumors to identify driver mutations for targeted therapy, suggest constitutional and familial testing for cancer predisposition syndromes, and select molecular targets worthy of further study.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Madhuri Kambhampati ◽  
Eshini Panditharatna ◽  
Sridevi Yadavilli ◽  
Karim Saoud ◽  
Sulgi Lee ◽  
...  

AbstractChildren diagnosed with brain tumors have the lowest overall survival of all pediatric cancers. Recent molecular studies have resulted in the discovery of recurrent driver mutations in many pediatric brain tumors. However, despite these molecular advances, the clinical outcomes of high grade tumors, including H3K27M diffuse midline glioma (H3K27M DMG), remain poor. To address the paucity of tissue for biological studies, we have established a comprehensive protocol for the coordination and processing of donated specimens at postmortem. Since 2010, 60 postmortem pediatric brain tumor donations from 26 institutions were coordinated and collected. Patient derived xenograft models and cell cultures were successfully created (76% and 44% of attempts respectively), irrespective of postmortem processing time. Histological analysis of mid-sagittal whole brain sections revealed evidence of treatment response, immune cell infiltration and the migratory path of infiltrating H3K27M DMG cells into other midline structures and cerebral lobes. Sequencing of primary and disseminated tumors confirmed the presence of oncogenic driver mutations and their obligate partners. Our findings highlight the importance of postmortem tissue donations as an invaluable resource to accelerate research, potentially leading to improved outcomes for children with aggressive brain tumors.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yiqun Zhang ◽  
Fengju Chen ◽  
Lawrence A. Donehower ◽  
Michael E. Scheurer ◽  
Chad J. Creighton

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.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii459-iii459
Author(s):  
Takashi Mori ◽  
Shigeru Yamaguchi ◽  
Rikiya Onimaru ◽  
Takayuki Hashimoto ◽  
Hidefumi Aoyama

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.


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