IDH3A and glioblastoma: Based on the 2016 update of the World Health Organization (WHO) classification of tumors of the central nervous system, the 5th edition published in 2021 advances the integration of molecular diagnostics with a histopathological assessment of brain tumors, including dividing the previously designated glioblastoma entities into isocitrate dehydrogenase (IDH)-wild-type glioblastoma and IDH-mutant glioblastoma (7).