IDH1 and astrocytoma (excluding glioblastoma): Table 1 summarizes some of the altered molecular profiles in gliomas. For instance, CDKN2A/B is one of the criteria to diagnose high-grade astrocytoma with piloid features alongside a piloid cytology, frequent MAPK pathway gene alterations, loss of ATRX nuclear expression, and a distinct DNA methylation pattern (135). Furthermore, to classify a tumor as oligodendroglioma both the IDH-mutation and 1p/19q codeletion should be identified (82, 135).