title: Analysis of the bHLH transcription factors Olig1 and Olig2 in brain tumors.
abstract: In the absence of specific markers, the histological diagnosis of oligodendroglial tumors is based on subjective qualitative criteria and remains controversial. Recently, two bHLH transcription factors involved in oligodendroglial specification, Olig1 and Olig2 have been proposed as potential markers of oligodendrogliomas. Expression of Olig1/2 was analyzed by in situ hybridization on 78 samples including 47 glial, 29 non-glial tumors, and two non-tumoral brain tissues. Both genes had a similar pattern of expression. Olig1 and Olig2 were expressed in 26/30 (87%) and 28/30 (93%) of oligodendroglial tumors respectively but in only 9% of glioblastomas (1/11). Olig genes were also expressed in the low-grade fibrillary astrocytomas (4/4) and anaplastic astrocytomas (2/2). No expression was found in non-glial tumors, except for one primary cerebral lymphoma. Double staining with PLP, NFH, GFAP showed that olig genes were expressed by mature, non-tumoral oligodendrocytes, but not by normal astrocytes or neurones. This study indicates that Olig1/2 expression clearly distinguishes pure Olig-negative glioblastomas from a wide spectrum of Olig-positive tumors including traditional oligodendrogliomas and oligoastrocytomas, glioblastomas with an oligodendroglial component (GBMO), and WHO grade 2 and 3 astrocytomas. Because Olig genes have a crucial role in oligodendroglial determination, our data could be of help in defining the real spectrum of oligodendroglial tumors.
authors.affiliation: INSERM U495, Laboratoire de Biologie des Interactions Neurones-Glie, Paris, France.
authors.forename: Lucinda
authors.initials: L
authors.lastname: Aguirre-Cruz
authors.forename: Karima
authors.initials: K
authors.lastname: Mokhtari
authors.forename: Khê
authors.initials: K
authors.lastname: Hoang-Xuan
authors.forename: Yannick
authors.initials: Y
authors.lastname: Marie
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Criniere
authors.forename: Sophie
authors.initials: S
authors.lastname: Taillibert
authors.forename: Manuel
authors.initials: M
authors.lastname: Lopes
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Delattre
authors.forename: Marc
authors.initials: M
authors.lastname: Sanson
mesh_terms: D001253:Astrocytes / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D017403:In Situ Hybridization; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D000076104:Oligodendrocyte Transcription Factor 2; D009836:Oligodendroglia / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D015342:DNA Probes; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D000076104:Oligodendrocyte Transcription Factor 2; C405707:OLIG1 protein, human; C405708:OLIG2 protein, human