Figure 1.

Timeline showing the principal dates of the histological and molecular classifications of gliomas. Classifying brain tumors has been the subject of many studies for several years. The first classification published in 1926 by Bailey and Cushing was based on histogenetics [51]. According to this classification, the presence of embryonic cells would be at the origin of tumor cells. The second classification proposed in 1949 by Kernohan JW, Mabon [52], includes grades of malignancy. The WHO proposed a new classification of gliomas in 1979 [53], which is internationally recognized and was revised in 1993, 2000, 2007 and 2016 [54,55,56,57]. These classifications are based on anatomopathological analysis of a representative glioma fragment (from biopsy or surgical resection) and “grading” elements. The International Society of Neuropathology was held from 1–3 May 2014 in Haarlem, the Netherlands [58]. The meeting reached consensus regarding the incorporation of non-histological data, such as molecular information, into the next WHO classification [55].