IDH1 and astrocytoma (excluding glioblastoma): It is of note, that 139 (59.9%) cases of glioblastomas and IDH mutant WHO grade 4 astrocytomas were histopathologically classified as WHO grade 4 tumors, whereas the remaining cases were histopathologically classified as grade 2 (17 cases; 7.3%) and grade 3 (76 cases; 32.8%) tumors and subsequently classified as WHO grade 4 solely due to molecular markers.