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Acta Neuropathologica Jun 2015Pilocytic astrocytomas (PAs) were recognized as a discrete clinical entity over 70 years ago. They are relatively benign (WHO grade I) and have, as a group, a 10-year... (Review)
Review
Pilocytic astrocytomas (PAs) were recognized as a discrete clinical entity over 70 years ago. They are relatively benign (WHO grade I) and have, as a group, a 10-year survival of over 90%. Many require merely surgical removal and only very infrequently do they progress to more malignant gliomas. While most show classical morphology, they may present a spectrum of morphological patterns, and there are difficult cases that show similarities to other gliomas, some of which are malignant and require aggressive treatment. Until recently, almost nothing was known about the molecular mechanisms involved in their development. The use of high-throughput sequencing techniques interrogating the whole genome has shown that single abnormalities of the mitogen-activating protein kinase (MAPK) pathway are exclusively found in almost all cases, indicating that PA represents a one-pathway disease. The most common mechanism is a tandem duplication of a ≈2 Mb-fragment of #7q, giving rise to a fusion between two genes, resulting in a transforming fusion protein, consisting of the N-terminus of KIAA1549 and the kinase domain of BRAF. Additional infrequent fusion partners have been identified, along with other abnormalities of the MAP-K pathway, affecting tyrosine kinase growth factor receptors at the cell surface (e.g., FGFR1) as well as BRAF V600E, KRAS, and NF1 mutations among others. However, while the KIAA1549-BRAF fusion occurs in all areas, the incidence of the various other mutations identified differs in PAs that develop in different regions of the brain. Unfortunately, from a diagnostic standpoint, almost all mutations found have been reported in other brain tumor types, although some retain considerable utility. These molecular abnormalities will be reviewed, and the difficulties in their potential use in supporting a diagnosis of PA, when the histopathological findings are equivocal or in the choice of individualized therapy, will be discussed.
Topics: Astrocytoma; Central Nervous System Neoplasms; Genetic Predisposition to Disease; Humans; Models, Molecular; Molecular Biology; Neuroimaging
PubMed: 25792358
DOI: 10.1007/s00401-015-1410-7 -
Cancer Reports (Hoboken, N.J.) Oct 2023A form of cancer called astrocytoma can develop in the brain or spinal cord and sometimes causes death. A detailed overview of the precise signaling cascade underlying... (Review)
Review
BACKGROUND
A form of cancer called astrocytoma can develop in the brain or spinal cord and sometimes causes death. A detailed overview of the precise signaling cascade underlying astrocytoma formation has not yet been revealed, although various factors have been investigated. Therefore, our objective was to unravel and summarize our current understanding of molecular genetics and associated signaling pathways with some possible therapeutic strategies for astrocytoma.
RECENT FINDINGS
In general, four different forms of astrocytoma have been identified in individuals, including circumscribed, diffuse, anaplastic, and multiforme glioblastoma, according to a recent literature review. All types of astrocytoma have a direct connection with some oncogenic signaling cascade. Common signaling is MAPK cascade, including Ras-Raf-ERK, up-regulated with activating EGFR/AKT/PTEN/mTOR and PDGFR. Recent breakthrough studies found that BRAF mutations, including KIAA1549: BRAF and BRAF V600E are responsible for astrocytoma progression. Additionally, cancer progression is influenced by mutations in some tumor suppressor genes, such as the Tp53/ATRX and MGMT mutant. As synthetic medications must cross the blood-brain barrier (BBB), modulating signal systems such as miRNA is the primary option for treating patients with astrocytoma. However, available surgery, radiation therapy, and experimental therapies such as adjuvant therapy, anti-angiogenic therapy, and EGFR-targeting antibody drug are the usual treatment for most types of astrocytoma. Similar to conventional anticancer medications, some phytochemicals slow tumor growth by simultaneously controlling several cellular proteins, including those involved in cell cycle regulation, apoptosis, metastatic spread, tyrosine kinase, growth factor receptor, and antioxidant-related proteins.
CONCLUSION
In conclusion, cellular and molecular signaling is directly associated with the development of astrocytoma, and a combination of conventional and alternative therapies can improve the malignancy of cancer patients.
Topics: Humans; Proto-Oncogene Proteins B-raf; Brain Neoplasms; Astrocytoma; Glioblastoma; ErbB Receptors
PubMed: 37675821
DOI: 10.1002/cnr2.1889 -
Neuro-oncology May 2018Intradural spinal tumors are rare tumors of the central nervous system. Due to the eloquence of the spinal cord and its tracts, the compact architecture of the cord and... (Review)
Review
Intradural spinal tumors are rare tumors of the central nervous system. Due to the eloquence of the spinal cord and its tracts, the compact architecture of the cord and nerves, and the infiltrative nature of some of these tumors, surgical resection is difficult to achieve without causing neurological deficits. Likewise, chemotherapy and radiotherapy are utilized more cautiously in the treatment of intradural spinal tumors than their cranial counterparts. Targeted therapies aimed at the genetic alterations and molecular biology tailored to these tumors would be helpful but are lacking.Here, we review the major types of intradural spinal tumors, with an emphasis on genetic alterations, molecular biology, and experimental therapies for these difficult to treat neoplasms.
Topics: Astrocytoma; Ependymoma; Humans; Prognosis; Spinal Neoplasms
PubMed: 29216380
DOI: 10.1093/neuonc/nox230 -
Acta Neuropathologica Oct 2023Pilocytic astrocytoma (PA), the most common pediatric brain tumor, is driven by aberrant mitogen-activated protein kinase signaling most commonly caused by BRAF gene...
Pilocytic astrocytoma (PA), the most common pediatric brain tumor, is driven by aberrant mitogen-activated protein kinase signaling most commonly caused by BRAF gene fusions or activating mutations. While 5-year overall survival rates exceed 95%, tumor recurrence or progression constitutes a major clinical challenge in incompletely resected tumors. Here, we used similarity network fusion (SNF) analysis in an integrative multi-omics approach employing RNA transcriptomic and mass spectrometry-based proteomic profiling to molecularly characterize PA tissue samples from 62 patients. Thereby, we uncovered that PAs segregated into two molecularly distinct groups, namely, Group 1 and Group 2, which were validated in three non-overlapping cohorts. Patients with Group 1 tumors were significantly younger and showed worse progression-free survival compared to patients with group 2 tumors. Ingenuity pathways analysis (IPA) and gene set enrichment analysis (GSEA) revealed that Group 1 tumors were enriched for immune response pathways, such as interferon signaling, while Group 2 tumors showed enrichment for action potential and neurotransmitter signaling pathways. Analysis of immune cell-related gene signatures showed an enrichment of infiltrating T Cells in Group 1 versus Group 2 tumors. Taken together, integrative multi-omics of PA identified biologically distinct and prognostically relevant tumor groups that may improve risk stratification of this single pathway driven tumor type.
Topics: Child; Humans; Multiomics; Proteomics; Astrocytoma; Brain Neoplasms; Action Potentials
PubMed: 37656187
DOI: 10.1007/s00401-023-02626-5 -
CNS Oncology Mar 2021Adult pilocytic astrocytoma (PA) is less prevalent than pediatric PA and is associated with a worse prognosis. In a literature review, we found that 88.3% of the... (Review)
Review
Adult pilocytic astrocytoma (PA) is less prevalent than pediatric PA and is associated with a worse prognosis. In a literature review, we found that 88.3% of the molecular alterations in adult PA are associated with MAPK pathway dysregulation. The most common alterations are fusions of . Understanding of the mechanisms underlying this pathway has evolved substantially, heralding advancements in specific targeted therapy. Here, we review clinical and molecular features of adult PA, characteristics predicting aggressive behavior and approaches to standard and investigational therapies. We highlight epigenetic profiling and integrated diagnosis as an essential component of classifying PA.
Topics: Adult; Astrocytoma; Brain Neoplasms; Child; Humans; Prognosis; Proto-Oncogene Proteins B-raf
PubMed: 33448230
DOI: 10.2217/cns-2020-0027 -
Medicine Nov 2022This study aimed to evaluate the diagnostic performance of dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging and apparent diffusion coefficient...
This study aimed to evaluate the diagnostic performance of dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging and apparent diffusion coefficient (ADC) for differentiating common posterior fossa tumors, pilocytic astrocytoma (PA), medulloblastoma (MB), and hemangioblastoma (HB). Between January 2016 and April 2022, we enrolled 23 (median age, 7 years [range, 2-26]; 12 female), 13 (10 years [1-24]; 3 female), and 12 (43 years [23-73]; 7 female) patients with PA, MB, and HB, respectively. Normalized relative cerebral blood volume and flow (nrCBV and nrCBF) and normalized mean ADC (nADCmean) were calculated from volume-of-interest and statistically compared. nADCmean was significantly higher in PA than in MB (PA: median, 2.2 [range, 1.59-2.65] vs MB: 0.93 [0.70-1.37], P < .001). nrCBF was significantly higher in HB than in PA and MB (PA: 1.10 [0.54-2.26] vs MB: 1.62 [0.93-3.16] vs HB: 7.83 [2.75-20.1], all P < .001). nrCBV was significantly different between all 3 tumor types (PA: 0.89 [0.34-2.28] vs MB: 1.69 [0.93-4.23] vs HB: 8.48 [4.59-16.3], P = .008 for PA vs MB; P < .001 for PA vs HB and MB vs HB). All tumors were successfully differentiated using an algorithmic approach with a threshold value of 4.58 for nrCBV and subsequent threshold value of 1.38 for nADCmean. DSC parameters and nADCmean were significantly different between PA, MB, and HB. An algorithmic approach combining nrCBV and nADCmean may be useful for differentiating these tumor types.
Topics: Humans; Female; Child; Medulloblastoma; Hemangioblastoma; Retrospective Studies; Diagnosis, Differential; Astrocytoma; Magnetic Resonance Imaging; Diffusion Magnetic Resonance Imaging; Perfusion; Cerebellar Neoplasms; Brain Neoplasms
PubMed: 36343086
DOI: 10.1097/MD.0000000000031708 -
Neuro-oncology Oct 2021Pediatric low-grade gliomas (pLGGs) are the most common brain tumor in children and are associated with lifelong clinical morbidity. Relative to their high-grade adult... (Review)
Review
Pediatric low-grade gliomas (pLGGs) are the most common brain tumor in children and are associated with lifelong clinical morbidity. Relative to their high-grade adult counterparts or other malignant childhood brain tumors, there is a paucity of authenticated preclinical models for these pLGGs and an incomplete understanding of their molecular and cellular pathogenesis. While large-scale genomic profiling efforts have identified the majority of pathogenic driver mutations, which converge on the MAPK/ERK signaling pathway, it is now appreciated that these events may not be sufficient by themselves for gliomagenesis and clinical progression. In light of the recent World Health Organization reclassification of pLGGs, and pilocytic astrocytoma (PA), in particular, we review our current understanding of these pediatric brain tumors, provide a conceptual framework for future mechanistic studies, and outline the challenges and pressing needs for the pLGG clinical and research communities.
Topics: Astrocytoma; Brain Neoplasms; Child; Glioma; Humans; MAP Kinase Signaling System; Signal Transduction
PubMed: 34131743
DOI: 10.1093/neuonc/noab138 -
SA Journal of Radiology 2024Leptomeningeal dissemination is a rare manifestation of pilocytic astrocytoma. It may occur with higher-grade tumours like medulloblastoma, ependymoma and high-grade...
UNLABELLED
Leptomeningeal dissemination is a rare manifestation of pilocytic astrocytoma. It may occur with higher-grade tumours like medulloblastoma, ependymoma and high-grade glioma, but is extremely rare with low-grade glioma. There has been a growing number of reported cases documenting leptomeningeal dissemination of pilocytic astrocytoma in the medical literature.
CONTRIBUTION
Description of a World Health Organization (WHO) Grade I suprasellar pilocytic astrocytoma with leptomeningeal dissemination in the brain and spinal cord which showed progression of the leptomeningeal nodules without tumour upgrading on long-term follow-up.
PubMed: 38840827
DOI: 10.4102/sajr.v28i1.2876 -
Brain Tumor Pathology Apr 2019Many breakthroughs have been made in the past decade regarding our knowledge of the biological basis of the diffuse gliomas, the most common primary central nervous... (Review)
Review
Many breakthroughs have been made in the past decade regarding our knowledge of the biological basis of the diffuse gliomas, the most common primary central nervous system (CNS) tumors. These tumors as a group are aggressive, associated with high mortality, and have a predilection for adults. However, a subset of CNS glial and glioneuronal tumors are characterized by a more circumscribed pattern of growth and occur more commonly in children and young adults. They tend to be indolent, but our understanding of anaplastic changes in these tumors continues to improve as diagnostic classifications evolve in the era of molecular pathology and more integrated and easily accessible clinical databases. The presence of anaplasia in pleomorphic xanthoastrocytomas and gangliogliomas is assigned a WHO grade III under the current classification, while the significance of anaplasia in pilocytic astrocytomas remains controversial. Recent data highlight the association of the latter with aggressive clinical behavior, as well as the presence of molecular genetic features of both pilocytic and diffuse gliomas, with the recognition that the precise terminology remains to be defined. We review the current concepts and advances regarding histopathology and molecular understanding of pilocytic astrocytomas, pleomorphic xanthoastrocytomas, and gangliogliomas, with a focus on their anaplastic counterparts.
Topics: Anaplasia; Astrocytoma; Brain Neoplasms; Carcinoma; Central Nervous System Neoplasms; Ganglioglioma; Glioma; Humans; Neuroglia; Proto-Oncogene Proteins B-raf
PubMed: 30859342
DOI: 10.1007/s10014-019-00336-z -
CNS Oncology Nov 2019Pleomorphic xanthoastrocytoma (PXA) is a rare primary CNS tumor. Recent advances in the molecular characterization are helping to define subtypes of tumor. The discovery... (Review)
Review
Pleomorphic xanthoastrocytoma (PXA) is a rare primary CNS tumor. Recent advances in the molecular characterization are helping to define subtypes of tumor. The discovery of mutations within a substantial percentage of PXA fosters a clearer understanding of the pathophysiology of these tumors with clear prognostic and therapeutic implications. These findings are expected to provide insight into the spectrum of clinical behavior observed in PXA, ranging from cure with surgery to diffuse dissemination throughout the neuraxis. This review details the clinical presentation including radiographic appearance of PXA. Pathology, including molecular pathology is discussed. Therapeutic management including surgical resection, radiotherapy and systemic therapies are reviewed.
Topics: Astrocytoma; Brain Neoplasms; Combined Modality Therapy; Humans; Prognosis
PubMed: 31535562
DOI: 10.2217/cns-2019-0009