Anaplastic gliomas in adults: an update

The current review summarizes recent advances on the oncogenesis, classification and treatment of adult anaplastic gliomas.

According to the 2016 WHO classification, three main molecular subgroups of adult diffuse anaplastic gliomas can be distinguished based on the 1p/19q codeletion and isocitrate dehydrogenase (IDH) mutation status. In the future, this classification may be further refined based on the telomerase reverse transcriptase promoter and alpha thalassemia/mental retardation syndrome X-linked mutation status, gene expression, DNA methylation and genomic profiling. Both newly diagnosed 1p/19q codeleted and 1p/19q-intact anaplastic gliomas benefit from the addition of chemotherapy to radiotherapy. However, in 1p/19q codeleted anaplastic gliomas, Procarbazine, CCNU and Vincristine chemotherapy seems more effective than temozolomide. At recurrence, 1p/19q-intact anaplastic gliomas do not benefit from the addition of bevacizumab to temozolomide. The use of poly(adenosine 5'-diphosphate-ribose) inhibitors may be another way of specifically targeting IDH-mutant gliomas in addition to specific inhibitors, demethylating agents and anti-IDH vaccines. v-raf murine sarcoma viral oncogene homolog B1 (BRAF)-mutant anaplastic xanthoastrocytomas and gangliogliomas may benefit from BRAF and mitogen-activated protein kinase inhibitors.

Molecular characterization is mandatory for integrated diagnosis and appropriate management of adult anaplastic gliomas. Both 1p/19q codeleted and 1p/19q-intact anaplastic diffuse gliomas benefit from early chemotherapy. At recurrence, preliminary data suggest a potential role for targeted therapies in specific molecular subgroups.