Olig-2 stained 22 (91.6%) of 24 oligodendrogliomas and all dysembryoplastic neuroepithelial tumors but also 24 (80%) of 30 glioblastoma multiforme and 8 (80%) of 10 pilocytic astrocytomas.
In the current study, the pattern of OLIG2 expression in a spectrum of 90 non-oligodendroglial pediatric gliomas varied from very low levels in the ependymomas (cellular and tanycytic) to high levels in pilocytic astrocytoma, and in the diffuse-type astrocytic tumors (WHO grades II-IV).