Open AccessHistopathological classification of Central Nervous System Tumors
Author(s) -
Mehdi Karkouri
Publication year - 2022
Publication title -
international journal for research and ethics
Language(s) - English
Resource type - Journals
ISSN - 2665-7481
DOI - 10.51766/ijre.v5i1.99
Subject(s) - atrx , cdkn2a , oligodendroglioma , brain tumor , astrocytoma , grading (engineering) , idh1 , pilocytic astrocytoma , dna methylation , pathology , biology , medicine , glioma , cancer research , gene , cancer , mutant , mutation , genetics , gene expression , ecology
The Central Nervous System Tumors (CNS) classification was traditionally based on the microscopic characteristics of the tumors, often supported by ancillary tissue-based tests such as immunohistochemical tests; however, there is a shift, these last decades, in integrating biological and molecular information in the classification of tumors. Hence, the last (5th) edition of the WHO Classification of CNS Tumors, recently released in 2021, introduced major changes, especially for gliomas. New tumor types and subtypes are introduced, some based on novel diagnostic technologies such as DNA methylome profiling. Arabic numerals are now used instead of the Roman numerals in the designation of the tumor grade, to align with the grading of theother organ tumors of the body and to avoid any typo mistake. Molecular information is more prominent and visible in the designation of the tumors because of the importance of certain genes or pathways in the development of such tumors. Beside IDH1 and IDH2, ATRX, TP53 and CDKN2A/B are the key diagnostic genes to assess for the diagnosis of astrocytoma IDH-mutant whereas 1p/19q, TERT promoter, CIC, FUBP1 and NOTCH1 are the key players for oligodendroglioma IDH-mutant-1p/19q-codeleted. TERT promoter, chromosomes 7/10 and EGFR must be assessed in IDH-wildtype glioblastoma. Whereas it is important that the classification of CNS Tumors must be the more precise possible, the integration of molecular information may undoubtedly limit the ability of laboratories and countries to use the classification and patients to benefit from the progress in the diagnosis and treatment of CNS Tumors.