OLIG2 (oligodendrocyte transcription factor 2) is a basic helix-loop-helix transcription factor essential for oligodendrocyte development and glioblastoma biology. In normal development, OLIG2 is required for oligodendrocyte specification and differentiation, functioning in combination with other transcription factors like SOX10 and NKX6.2 to directly reprogram human fibroblasts into oligodendrocyte-like cells within 16 days 1. During neural development, OLIG2+ cells differentiate from PAX6+ neural stem cells around day 12, subsequently expressing NKX2.2 and SOX10 as they progress toward mature oligodendrocytes 2. In glioblastoma pathology, OLIG2 plays a critical oncogenic role as part of a core set of neurodevelopmental transcription factors (POU3F2, SOX2, SALL2, and OLIG2) essential for tumor propagation 3. OLIG2 functions redundantly with ASCL1 to drive glioblastoma initiation and regulate tumor cell heterogeneity 4. Notably, OLIG2+ glioma cells exhibit distinct biological properties, promoting single-cell vessel co-option through Wnt7b signaling while preserving the blood-brain barrier, contrasting with OLIG2-negative cells that form dense perivascular collections and promote angiogenesis 5. This dual role in normal oligodendrocyte development and glioblastoma progression makes OLIG2 a significant therapeutic target.