OLIG2 and central nervous system cancer: A stereotactic brain biopsy and subsequent neuropathological evaluations were performed, resulting in a glioma tumor isocitrate dehydrogenase 1 (IDH-1) and 2 (IDH-2) wild type, glial fibrillary acidic protein (GFAP) and oligodendrocyte transcription factor 2 (Olig2) positive.