{"entity":{"id":"paper-who-2021-cns-louis-neuro-oncology-2021","kind":"paper","name":"The 2021 WHO classification of tumours of the central nervous system: a summary","aka":[],"tldr":"The fifth-edition brain tumour classification makes molecular markers such as IDH mutation, 1p/19q codeletion and methylation class central to diagnosis, renaming and regrading many tumours, including separating IDH-mutant astrocytoma from glioblastoma.","summary":"Summary of the 2021 WHO classification of central nervous system tumours introducing integrated histological and molecular diagnoses, Arabic numeral grading within tumour types, new tumour types and families (paediatric-type diffuse gliomas, molecularly defined ependymomas and medulloblastoma groups), and grading of IDH-mutant astrocytoma up to grade 4 with CDKN2A/B deletion.","asOf":"2026-09-17","links":[{"label":"Neuro Oncol 2021","url":"https://doi.org/10.1093/neuonc/noab106"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/34185076/"}],"tags":[],"related":[],"cancers":["idh-mutant-astrocytoma","oligodendroglioma","meningioma","paediatric-high-grade-glioma","spinal-cord-tumours","cns-germ-cell-tumours","medulloblastoma-group-3-4","medulloblastoma-shh","medulloblastoma-wnt"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":["neuro-oncology"],"dependsOn":[],"notes":[],"journal":"Neuro-Oncology","year":2021,"doi":"10.1093/neuonc/noab106","pmid":"34185076","authors":"Louis DN, Perry A, Wesseling P, et al.","paperType":"guideline","findings":[],"whatItMeans":"Every brain tumour page on this site uses these names and grades; a tumour called glioblastoma before 2021 may now be an IDH-mutant astrocytoma with a different outlook and treatment.","caveats":["Requires molecular testing that is not available everywhere, leaving some diagnoses as not otherwise specified."],"changedPractice":true},"route":"/key-papers/paper-who-2021-cns-louis-neuro-oncology-2021/","neighbours":{"cancer":[{"id":"idh-mutant-astrocytoma","kind":"cancer","name":"Astrocytoma, IDH-mutant (grades 2 to 4)","route":"/cancers/idh-mutant-astrocytoma/"},{"id":"cns-germ-cell-tumours","kind":"cancer","name":"Central nervous system germ cell tumours (germinoma and non-germinomatous)","route":"/cancers/cns-germ-cell-tumours/"},{"id":"medulloblastoma-group-3-4","kind":"cancer","name":"Group 3 and group 4 medulloblastoma (non-WNT/non-SHH)","route":"/cancers/medulloblastoma-group-3-4/"},{"id":"meningioma","kind":"cancer","name":"Meningioma","route":"/cancers/meningioma/"},{"id":"oligodendroglioma","kind":"cancer","name":"Oligodendroglioma, IDH-mutant and 1p/19q-codeleted","route":"/cancers/oligodendroglioma/"},{"id":"paediatric-high-grade-glioma","kind":"cancer","name":"Paediatric high-grade glioma (excluding diffuse midline glioma)","route":"/cancers/paediatric-high-grade-glioma/"},{"id":"medulloblastoma-shh","kind":"cancer","name":"SHH-activated medulloblastoma","route":"/cancers/medulloblastoma-shh/"},{"id":"spinal-cord-tumours","kind":"cancer","name":"Spinal cord tumours (intramedullary and intradural)","route":"/cancers/spinal-cord-tumours/"},{"id":"medulloblastoma-wnt","kind":"cancer","name":"WNT-activated medulloblastoma","route":"/cancers/medulloblastoma-wnt/"}],"journal":[{"id":"neuro-oncology","kind":"journal","name":"Neuro-Oncology","route":"/journals/neuro-oncology/"}]}}