World Health Organization 2021 Classification of Central Nervous System Tumors and Implications for Therapy for Adult-Type Gliomas

Importance: Previous histologic classifications of brain tumors have been limited by discrepancies in diagnoses reported by neuropathologists and variability in outcomes and response to therapies. Such diagnostic discrepancies have impaired clinicians' ability to select the most appropriate therapies for patients and have allowed heterogeneous populations of patients to be enrolled in clinical trials, hindering the development of more effective therapies. In adult-type diffuse gliomas, histologic classification has a particularly important effect on clinical care. Observations: In 2021, the World Health Organization published the fifth edition of the Classification of Tumors of the Central Nervous System. This…