{"database":"biostudies-arrayexpress","file_versions":[],"scores":null,"additional":{"omics_type":["Metabolomics","Unknown","Transcriptomics","Genomics","Proteomics"],"submitter":["Arnault TAUZIEDE"],"study_type":["methylation profiling by array"],"organism":["Yersinia enterocolitica"],"species":["Yersinia enterocolitica"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/E-MTAB-17457"],"description":["Two studies originating from the same team have previously suggested the existence of tectal glioma (TG) as a distinct pediatric low grade circumscribed astrocytic tumor type enriched in KRAS alterations or KRAS and BRAF concomitant alterations, and characterized by a distinct methylation profile. Although the majority of these tumors display a pilocytic astrocytoma (PA) morphology, the imprecise terminology of “glioma” was preferred by these authors. The inclusion of the entity “tectal glioma with KRAS mutation” in a future WHO classification is still under discussion. In this context, we performed a comprehensive analysis of 35 glial tumors located in the tectum including clinical, radiological, histopathological, and molecular data. The majority of tumors encountered were pilocytic astr"],"repository":["biostudies-arrayexpress"],"sample_protocol":["Sample Collection - Genomic DNA was extracted from fresh-frozen or formalin-fixed and paraffin-embedded (FFPE) tissue samples.","Scaning - Genomic DNA was extracted from fresh-frozen or formalin-fixed and paraffin-embedded (FFPE) tissue samples.","Nucleic Acid Extraction - Genomic DNA was extracted from fresh-frozen or formalin-fixed and paraffin-embedded (FFPE) tissue samples.","Labeling - Genomic DNA was extracted from fresh-frozen or formalin-fixed and paraffin-embedded (FFPE) tissue samples.","Hybridization - Genomic DNA was extracted from fresh-frozen or formalin-fixed and paraffin-embedded (FFPE) tissue samples."],"figure_sub":["MIAME Score","Raw Data","Organization","Assays and Data","Processed Data","MAGE-TAB Files","Array Designs"],"pubmed_authors":["Arnault TAUZIEDE"],"data_protocol":["Data Transformation - Each sample was individually normalized by performing a background correction (shifting of the 5% percentile of negative control probe intensities to 0) and a dye-bias correction (scaling of the mean of normalization control probe intensities to 10,000) for both color channels. Subsequently, a correction for the type of material tissue (FFPE/frozen) and array type (450k/EPIC) was performed by fitting univariable, linear models to the log2-transformed intensity values (removeBatchEffect function, limma package version 3.30.11). The methylated and unmethylated signals were corrected individually. Beta-values were calculated from the retransformed intensities using an offset of 100 (as recommended by Illumina). All samples were checked for duplicates by pairwise correlat"],"additional_accession":[]},"is_claimable":false,"name":"TECTAL GLIOMA VERSUS PILOCYTIC ASTROCYTOMA: REVISITING TUMOR CLASSIFICATION IN LIGHT OF MOLECULAR HETEROGENEITY","description":"Two studies originating from the same team have previously suggested the existence of tectal glioma (TG) as a distinct pediatric low grade circumscribed astrocytic tumor type enriched in KRAS alterations or KRAS and BRAF concomitant alterations, and characterized by a distinct methylation profile. Although the majority of these tumors display a pilocytic astrocytoma (PA) morphology, the imprecise terminology of “glioma” was preferred by these authors. The inclusion of the entity “tectal glioma with KRAS mutation” in a future WHO classification is still under discussion. In this context, we performed a comprehensive analysis of 35 glial tumors located in the tectum including clinical, radiological, histopathological, and molecular data. The majority of tumors encountered were pilocytic astr","dates":{"release":"2026-08-19T00:00:00Z","modification":"2026-08-19T01:00:44.594Z","creation":"2026-08-04T11:38:45.055Z"},"accession":"E-MTAB-17457","cross_references":{"EFO":["EFO_0002944","EFO_0003814","EFO_0003813","EFO_0002759","EFO_0005518","EFO_0003816","EFO_0003815"]}}