For the first time, the WHO (World Health Organization) Classification of Tumors of the Central Nervous System uses molecular and histological analysis together to define brain tumor entities. The new concept for how CNS tumor diagnosis should be structured, moves the IDH status into focus. The algorithm for classification of the diffuse gliomas often proceeds from IDH1 R132H histology first to molecular genetic features next.
Louis DN et al., The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary. Acta Neuropathol. 2016, 131(6):803-820. >> Reference Link