In the diagnostic process of an HGG, in 4/11 (36%) centers NGS is always applied by default, and in another 5/11 (46%) it is only used for specific patient groups, for instance patients aged under 55 or 60 years, when immunohistochemistry is not sufficient for the diagnosis of an IDH1 R132H wild-type glioblastoma. Here, IDH1 is linked to glioblastoma.