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Neuro-oncology Oct 2023Distinguishing the cellular origins of childhood brain tumors is key for understanding tumor initiation and identifying lineage-restricted, tumor-specific therapeutic...
BACKGROUND
Distinguishing the cellular origins of childhood brain tumors is key for understanding tumor initiation and identifying lineage-restricted, tumor-specific therapeutic targets. Previous strategies to map the cell-of-origin typically involved comparing human tumors to murine embryonal tissues, which is potentially limited due to species-specific differences. The aim of this study was to unravel the cellular origins of the 3 most common pediatric brain tumors, ependymoma, pilocytic astrocytoma, and medulloblastoma, using a developing human cerebellar atlas.
METHODS
We used a single-nucleus atlas of the normal developing human cerebellum consisting of 176 645 cells as a reference for an in-depth comparison to 4416 bulk and single-cell transcriptome tumor datasets, using gene set variation analysis, correlation, and single-cell matching techniques.
RESULTS
We find that the astroglial cerebellar lineage is potentially the origin for posterior fossa ependymomas. We propose that infratentorial pilocytic astrocytomas originate from the oligodendrocyte lineage and MHC II genes are specifically enriched in these tumors. We confirm that SHH and Group 3/4 medulloblastomas originate from the granule cell and unipolar brush cell lineages. Radiation-induced gliomas stem from cerebellar glial lineages and demonstrate distinct origins from the primary medulloblastoma. We identify tumor genes that are expressed in the cerebellar lineage of origin, and genes that are tumor specific; both gene sets represent promising therapeutic targets for future study.
CONCLUSION
Based on our results, individual cells within a tumor may resemble different cell types along a restricted developmental lineage. Therefore, we suggest that tumors can arise from multiple cellular states along the cerebellar "lineage of origin."
Topics: Child; Humans; Animals; Mice; Medulloblastoma; Brain Neoplasms; Glioma; Astrocytoma; Ependymoma; Cerebellum; Cerebellar Neoplasms
PubMed: 37534924
DOI: 10.1093/neuonc/noad124 -
Frontiers in Oncology 2023Ependymomas are rare glial tumors with clinical and biological heterogeneity, categorized into supratentorial ependymoma, posterior fossa ependymoma, and spinal cord... (Review)
Review
Ependymomas are rare glial tumors with clinical and biological heterogeneity, categorized into supratentorial ependymoma, posterior fossa ependymoma, and spinal cord ependymoma, according to anatomical localization. Spinal ependymoma comprises four different types: spinal ependymoma, spinal ependymoma -amplified, myxopapillary ependymoma, and subependymoma. The clinical onset largely depends on the spinal location of the tumor. Both non-specific and specific sensory and/or motor symptoms can be present. Owing to diverse features and the low incidence of spinal ependymomas, most of the current clinical management is derived from small retrospective studies, particularly in adults. Treatment involves primarily surgical resection, aiming at maximal safe resection. The use of radiotherapy remains controversial and the optimal dose has not been established; it is usually considered after subtotal resection for WHO grade 2 ependymoma and for WHO grade 3 ependymoma regardless of the extent of resection. There are limited systemic treatments available, with limited durable results and modest improvement in progression-free survival. Thus, chemotherapy is usually reserved for recurrent cases where resection and/or radiation is not feasible. Recently, a combination of temozolomide and lapatinib has shown modest results with a median progression-free survival (PFS) of 7.8 months in recurrent spinal ependymomas. Other studies have explored the use of temozolomide, platinum compounds, etoposide, and bevacizumab, but standard treatment options have not yet been defined. New treatment options with targeted treatments and immunotherapy are being investigated. Neurological and supportive care are crucial, even in the early stages. Post-surgical rehabilitation can improve the consequences of surgery and maintain a good quality of life, especially in young patients with long life expectancy. Here, we focus on the diagnosis and treatment recommendations for adults with spinal ependymoma, and discuss recent molecular advances and new treatment perspectives.
PubMed: 38074692
DOI: 10.3389/fonc.2023.1301179 -
Journal of Neuro-oncology Sep 2023Despite aggressive management consisting of surgery, radiation therapy (RT), and systemic therapy given alone or in combination, a significant proportion of patients... (Review)
Review
Despite aggressive management consisting of surgery, radiation therapy (RT), and systemic therapy given alone or in combination, a significant proportion of patients with brain tumors will experience tumor recurrence. For these patients, no standard of care exists and management of either primary or metastatic recurrent tumors remains challenging.Advances in imaging and RT technology have enabled more precise tumor localization and dose delivery, leading to a reduction in the volume of health brain tissue exposed to high radiation doses. Radiation techniques have evolved from three-dimensional (3-D) conformal RT to the development of sophisticated techniques, including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and stereotactic techniques, either stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT). Several studies have suggested that a second course of RT is a feasible treatment option in patients with a recurrent tumor; however, survival benefit and treatment related toxicity of reirradiation, given alone or in combination with other focal or systemic therapies, remain a controversial issue.We provide a critical overview of the current clinical status and technical challenges of reirradiation in patients with both recurrent primary brain tumors, such as gliomas, ependymomas, medulloblastomas, and meningiomas, and brain metastases. Relevant clinical questions such as the appropriate radiation technique and patient selection, the optimal radiation dose and fractionation, tolerance of the brain to a second course of RT, and the risk of adverse radiation effects have been critically discussed.
Topics: Humans; Re-Irradiation; Neoplasm Recurrence, Local; Brain Neoplasms; Radiotherapy, Conformal; Radiosurgery; Cerebellar Neoplasms
PubMed: 37624529
DOI: 10.1007/s11060-023-04407-2 -
Neuro-oncology Jul 2023A methylation-based classification of ependymoma has recently found broad application. However, the diagnostic advantage and implications for treatment decisions remain...
BACKGROUND
A methylation-based classification of ependymoma has recently found broad application. However, the diagnostic advantage and implications for treatment decisions remain unclear. Here, we retrospectively evaluate the impact of surgery and radiotherapy on outcome after molecular reclassification of adult intracranial ependymomas.
METHODS
Tumors diagnosed as intracranial ependymomas from 170 adult patients collected from 8 diagnostic institutions were subjected to DNA methylation profiling. Molecular classes, patient characteristics, and treatment were correlated with progression-free survival (PFS).
RESULTS
The classifier indicated an ependymal tumor in 73.5%, a different tumor entity in 10.6%, and non-classifiable tumors in 15.9% of cases, respectively. The most prevalent molecular classes were posterior fossa ependymoma group B (EPN-PFB, 32.9%), posterior fossa subependymoma (PF-SE, 25.9%), and supratentorial ZFTA fusion-positive ependymoma (EPN-ZFTA, 11.2%). With a median follow-up of 60.0 months, the 5- and 10-year-PFS rates were 64.5% and 41.8% for EPN-PFB, 67.4% and 45.2% for PF-SE, and 60.3% and 60.3% for EPN-ZFTA. In EPN-PFB, but not in other molecular classes, gross total resection (GTR) (P = .009) and postoperative radiotherapy (P = .007) were significantly associated with improved PFS in multivariable analysis. Histological tumor grading (WHO 2 vs. 3) was not a predictor of the prognosis within molecularly defined ependymoma classes.
CONCLUSIONS
DNA methylation profiling improves diagnostic accuracy and risk stratification in adult intracranial ependymoma. The molecular class of PF-SE is unexpectedly prevalent among adult tumors with ependymoma histology and relapsed as frequently as EPN-PFB, despite the supposed benign nature. GTR and radiotherapy may represent key factors in determining the outcome of EPN-PFB patients.
Topics: Adult; Humans; Retrospective Studies; DNA Methylation; Prognosis; Brain Neoplasms; Ependymoma
PubMed: 36734226
DOI: 10.1093/neuonc/noad030 -
Radiologie (Heidelberg, Germany) Aug 2023Tumors of the posterior fossa account for about 50-55% of brain tumors in childhood. (Review)
Review
CLINICAL ISSUE
Tumors of the posterior fossa account for about 50-55% of brain tumors in childhood.
DIAGNOSTIC WORKUP
The most frequent tumor entities are medulloblastomas, pilocytic astrocytomas, ependymomas, diffuse midline gliomas and atypical teratoid-rhabdoid tumors. Neuroradiological differential diagnosis with magnetic resonance imaging (MRI) is of considerable importance for preoperative planning as well as planning of follow-up therapy.
PERFORMANCE
Most important findings for differential diagnosis of pediatric posterior fossa tumors are tumor location, patient age and the intratumoral apparent diffusion assessed by diffusion-weighted imaging.
ACHIEVEMENTS
Advanced MR techniques like MRI perfusion and MR spectroscopy can be helpful both in the initial differential diagnosis and in tumor surveillance, but exceptional characteristics of certain tumor entities should be kept in mind.
PRACTICAL RECOMMENDATIONS
Standard clinical MRI sequences including diffusion-weighted imaging are the main diagnostic tool in evaluating posterior fossa tumors in children. Advanced imaging methods can be helpful, but should never be interpreted separately from conventional MRI sequences.
Topics: Child; Humans; Medulloblastoma; Infratentorial Neoplasms; Brain Neoplasms; Magnetic Resonance Imaging; Cerebellar Neoplasms
PubMed: 37306749
DOI: 10.1007/s00117-023-01159-y