Of course, further glioma classification systems exist, and as of the 2016 edition of the WHO classification, gliomas are classified based not only on histopathologic appearance but also on well-established molecular parameters.22 The incorporation of molecular features has most notably affected the classification of astrocytic and oligodendroglial tumours, which are now grouped together as diffuse gliomas, on the basis of growth pattern, behaviour, and shared IDH1 status. The gene discussed is IDH1; the disease is central nervous system cancer.