Establishing a prognostic threshold for total copy number variation within adult IDH-mutant grade II/III astrocytomas

Acta Neuropathologica Communications 7, Article number: 121 (2019) | Download Citation

Prior to the 2016 WHO update, adult astrocytomas were graded exclusively by histologic features, where grade III anaplastic astrocytomas were separated from grade II diffuse infiltrating astrocytomas on the basis of mitotic figures, and glioblastomas (GBM; grade IV) were defined based on the presence of microvascular proliferation and/or tumor necrosis [9]. With the establishment of the 2016 WHO Classification of Tumours of the Central Nervous System guidelines, adult astrocytomas have been segregated into IDH-wildtype and IDH-mutant groups due to the significant prognostic advantage conferred by the presence of an IDH1 or IDH2 mutation [9, 14]. Since this update, much work has been done to establish additional prognostic factors in both IDH-wildtype and IDH-mutant astrocytomas to further subclassify these groups and to aid in the understanding of the underlying biology [1,2,3, 5].