Figure 3.

OLIG1 is expressed at low levels in most astroglial tumors. (A, C, E, G) Histological analysis and (B, D, F, H) in situ hybridization by using an OLIG1 cRNA probe were performed on samples of: (A, B) nonneoplastic human cortex, (C, D) fibrillary astrocytoma, (E, F) anaplastic astrocytoma, and (G, H) PA. Note astrocytic cells in astrocytomas with pleomorphic nuclei, large amounts of cytoplasm, and dense fiber bundles. Expression of OLIG1 in these tumors was low and contrasted strong expression in oligodendroglioma (see Fig. 2). (Bar = 50 μm.)