OLIG1 and glioma: In agreement with previous studies demonstrating glioma expression of oligodendrocyte progenitor cell transcription factor Olig1/2 and surface antigen NG2 [1]–[3], the concomitant expression of A2B5 (a marker for multiple types of progenitor cells in glial lineage [20]–[27], [41]), PDGFRα (a marker for early oligodendrocyte progenitor cells at O-2A stage [22], [25], [26], [42]–[44]) and O4 (a marker for late oligodendrocyte progenitor cells [29]) suggests that glioma cells, irrespective of their morphological characteristics, are committed to the oligodendrocyte lineage.