Current WHO Guidelines and the Critical Role of Genetic Parameters in the Classification of Glioma: Opportunities for Immunotherapy

Opinion statement In the 5 years since the fourth edition of the WHO Classification of Tumors of the Central Nervous System (CNS) (revised) was released, the development of targeted sequencing and omics technology has helped researchers in the field of neuro-oncology to identify some new tumor types in clinical practice, as well as a series of genetic parameters related to tumor occurrence and development, poor prognosis, treatment response, etc. These findings not only provide basic knowledge for the classification of glioma, but also promote the progress of the treatment of gliomas. As a revolution in cancer treatment, immunotherapy has become a promising strategy since the pioneering discovery of lymphatics in the CNS. The advancement and clinical application of immunotherapy have strengthened the demand for accurate classification of glioma. In June 2021, the WHO and the International Agency for Research on Cancer (IARC) published the fifth edition of the WHO Classification of Tumors of the CNS. The fifth edition focuses on advancing the role of genetic parameters in the classification of glioma and divides glioma into more biologically and molecularly defined entities, with better natural history characteristics, and introduced new tumor types and subtypes, especially in the pediatric population. Most importantly, these updated classifications will enable clinicians to better assess the prognosis and formulate the optimal treatment of gliomas.