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.
Azzarelli
Biagio
B
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
Miravalle
Leticia
L
Vidal
Ruben
R
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