Search results for "Medulloblastoma"
showing 10 items of 36 documents
Opposing Effects of CREBBP Mutations Govern the Phenotype of Rubinstein-Taybi Syndrome and Adult SHH Medulloblastoma
2018
Recurrent mutations in chromatin modifiers are specifically prevalent in adolescent or adult patients with Sonic hedgehog-associated medulloblastoma (SHH MB). Here, we report that mutations in the acetyltransferase CREBBP have opposing effects during the development of the cerebellum, the primary site of origin of SHH MB. Our data reveal that loss of Crebbp in cerebellar granule neuron progenitors (GNPs) during embryonic development of mice compromises GNP development, in part by downregulation of brain-derived neurotrophic factor (Bdnf). Interestingly, concomitant cerebellar hypoplasia was also observed in patients with Rubinstein-Taybi syndrome, a congenital disorder caused by germline mu…
Preradiation chemotherapy of children and young adults with malignant brain tumors: Results of the german pilot trial HIT'88/'89
1998
Background Preradiation chemotherapy could be beneficial in malignant brain tumors, because the blood-brain tumor-barrier is disrupted after surgery, bone marrow recovery--essential for intense chemotherapy--is still intact, and CNS toxicity and ototoxicity of active drugs are lower before irradiation of a child's brain. Patients and methods A neoadjuvant phase 2 and a single arm pilot trial were initiated to investigate the efficacy and toxicity of an intense multidrug regimen before radiotherapy in 147 patients aged between 3 and 29; 9 years with medulloblastoma (94), malignant glioma (22), ependymoma (21), and stPNET (10). They were treated with one or two cycles consisting of procarbazi…
Differentiation in medulloblastomas: correlation between the immunocytochemical demonstration of photoreceptor markers (S-antigen, rod-opsin) and the…
1989
Biopsy specimens of 66 medulloblastomas were investigated by means of S-antigen and rod-opsin immunocytochemistry. The patients were operated between 1969 and 1988 and the medical records were retrospectively evaluated to correlate the immunocytochemical features of the tumors to the course of the disease. S-antigen- and rod-opsin-immunoreactive tumor cells were found in 19 out of 66 cases. Since in the normal non-neoplastic state immunoreactive S-antigen and rod-opsin are restricted to retinal photoreceptors and a class of pinealocytes derived from photoreceptor cells, the occurrence of these proteins in certain tumor cells of medulloblastomas suggests a differentiation of these cells alon…
Different immunohistochemical levels of Hsp60 and Hsp70 in a subset of brain tumors and putative role of Hsp60 in neuroepithelial tumorigenesis
2013
In this work we analysed, by immunohistochemistry, a series of brain tumors to detect the levels and cellular distribution of Hsp60 and Hsp70. We found that Hsp60 levels were significantly higher than those of Hsp70 in neuroepithelial tumors, while levels of both molecules were not significantly different from each other in meningeal neoplasms. In particular, Hsp60 immunopositivity was present mainly at the cytoplasmic level, while Hsp70 immunopositivity was found both in the cytoplasm and in the nucleus of tumor cells. The levels of these molecules in healthy control cells were always very low. Finally, Hsp60 and Hsp70 levels did not correlate with the different types (WHO grade) of neopla…
Long-term follow-up of children with magnetic resonance imaging and ultrasound after treatment of brain tumors
1987
This paper compares the results of MRI and US follow-up examinations of 46 children who had undergone surgery for brain tumors. The cases included 42 posterior fossa tumors, 3 supratentorial tumors and 1 upper cervical spinal cord tumor. US examination proved to be less specific and sensitive than MRI. However, when a "bone window" is available, US is, because of the ease of its application, better suited for frequent routine examinations. Long-term follow-up should, therefore, consist of frequent regular US examinations combined with yearly MRI examinations.
Susceptibility-weighted magnetic resonance imaging of cerebrovascular sequelae after radiotherapy for pediatric brain tumors
2017
Due to sensitive neuroimaging techniques, cerebrovascular complications such as cerebral microbleeds (CMB) and cerebral cavernous malformations (CCM) are increasingly recognized as considerable late effects after treatment for pediatric brain tumor. The aim of this study was to analyze CMB in a cohort of patients after cranial irradiation therapy for medulloblastoma or other pediatric brain tumors using susceptibility-weighted magnetic resonance imaging (SWI).Forty former pediatric brain tumor patients were enrolled in this prospective cross-sectional study and examined by cranial MRI including SWI sequences. Cerebral microbleeds, clinical symptoms and disability were evaluated.Thirty-six (…
Etoposide Treatment in Recurrent Medulloblastoma
1994
Five consecutive patients with recurrent medulloblastoma received etoposide 120 mg/m2 for 5 to 7 days at 2 to 4-week intervals. Three patients with neuroaxis dissemination received additional intrathecal chemotherapy with methotrexate, cytosine arabinoside and prednisone. Toxicity consisted of alopecia and mild neutropenia. Complete response was registered in two patients, partial response in one. Median survival was 19 months with the 3 responders living 6, 30 and 60+ months. Etoposide seems to be an active agent in medulloblastoma.
The histology of brain tumors for 67 331 children and 671 085 adults diagnosed in 60 countries during 2000-2014: a global, population-based study (CO…
2021
Abstract Background Global variations in survival for brain tumors are very wide when all histological types are considered together. Appraisal of international differences should be informed by the distribution of histology, but little is known beyond Europe and North America. Methods The source for the analysis was the CONCORD database, a program of global surveillance of cancer survival trends, which includes the tumor records of individual patients from more than 300 population-based cancer registries. We considered all patients aged 0-99 years who were diagnosed with a primary brain tumor during 2000-2014, whether malignant or nonmalignant. We presented the histology distribution of th…
Radiation-induced vascular changes in the intracranial irradiation field in medulloblastoma survivors: An MRI study
2019
While survival times after treatment of medulloblastoma are increasing, little is known about radiochemotherapy (RCT)-induced cerebrovascular changes. High resolution vessel wall imaging (VWI) sequences are an emerging tool for the evaluation of cerebrovascular diseases. We performed VWI in medulloblastoma long-term survivors to screen for late sequelae of RCT.Twenty-two pediatric medulloblastoma survivors (mean age 25.8 years (10-53 years); 16.3 years (mean) post primary RCT (range 1-45 years)) underwent 2D VWI-MRI. Vessel wall thickening, contrast enhancement and luminal narrowing were analyzed. The findings were correlated with the patients' radiation protocols.Vessel wall changes were o…
Antitumor Effects of a Combined 5-Aza-2′Deoxycytidine and Valproic Acid Treatment on Rhabdomyosarcoma and Medulloblastoma in Ptch Mutant Mice
2009
Abstract Patched (Ptch) heterozygous mice develop medulloblastoma (MB) and rhabdomyosarcoma (RMS) resembling the corresponding human tumors. We have previously shown that epigenetic silencing of the intact Ptch allele contributes to tumor formation in this model. Here, we investigated whether targeting of epigenetic silencing mechanisms could be useful in the treatment of Ptch-associated cancers. A reduction of endogenous DNA methyltransferase1 (Dnmt1) activity significantly reduced tumor incidence in heterozygous Ptch knockout mice. A combined treatment with the Dnmt inhibitor 5-aza-2′deoxycytidine (5-aza-dC) and the histone deacetlyase (HDAC) inhibitor valproic acid (VPA) efficiently prev…