IDH1 and glioma: Moreover, long-held clinical assumptions such as the impact of age and tumor grade on the outcome of patients with diffuse glioma are challenged in the era of integrated histomolecular glioma classification based on IDH mutation and 1p/19q codeletion status.16 New, contemporary cohort studies on patients with IDH-mutant gliomas are needed on all aspects of diagnosis and treatment to understand the outcome of patients.