Immunolocalization of the oligodendrocyte transcription factor 1 (Olig1) in brain tumors.
Recent in situ hybridization studies showed that mRNA levels of OLIG1 and OLIG2 transcription factors are elevated in oligodendrogliomas. We raised polyclonal antibodies against a synthetic peptide homologous to the human transcription factor Olig1 and studied by immunohistochemistry the expression of Olig1 in 84 brain tumors and in non-neoplastic brain tissues. All oligodendrogliomas, oligoastrocytomas, and dysembryoplastic neuroepithelial tumors showed moderate to strong intranuclear immunoreactivity in cells morphologically identified as oligodendrocytes. In addition, some astrocytomas showed a slight to moderate intranuclear immunoreactivity. None of the other neuroepithelial and non-neuroepithelial tumors showed nuclear immunoreactivity. Double immunostaining of oligodendrogliomas, oligoastrocytomas, and glioblastoma multiforme (GBM) using antibodies against Olig1 and GFAP showed the presence of 3 different cell populations: 1) immunopositive for Olig1 and immunonegative for GFAP, histologically identified as oligodendrocytes; 2) immunopositive only for GFAP, histologically identified as astrocytes; and 3) immunonegative for both antibodies ("null cells"), histologically observed as a population of cells usually with round nuclei and a small amount of cytoplasm. The use of double immunostaining facilitated the distinction among these 3 different tumors. In summary, the use of immunohistochemistry using Olig1 antibodies alone or in combination with anti-GFAP antibody, which can be performed in the routine diagnostic setting, may help in the diagnosis of neuroepithelial tumors.
Department of Pathology, Laboratory Medicine, Division of Neuropathology, Indiana University School of Medicine, 635 Barnhill Drive, MS B029, Indianapolis, IN 46201, USA. bazzarel@iupui.edu
Biagio
B
Azzarelli
Leticia
L
Miravalle
Ruben
R
Vidal
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001254:Astrocytoma / Q000378:metabolism / Q000473:pathology; D051792:Basic Helix-Loop-Helix Proteins; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000378:metabolism*; D002452:Cell Count; D002648:Child; D002675:Child, Preschool; D004268:DNA-Binding Proteins / Q000276:immunology / Q000378:metabolism*; D004806:Ependymoma / Q000378:metabolism / Q000473:pathology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000276:immunology / Q000378:metabolism*; D009837:Oligodendroglioma / Q000378:metabolism / Q000473:pathology
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; C405707:OLIG1 protein, human