Artikel
Anaplastic actrocytomas show highest expression levels of differentiation gene OLIG2
Anaplastische Astrozytome zeigen die höchste Expression des Differenzierungsgens OLIG2
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Veröffentlicht: | 11. April 2007 |
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Objective: We examined the gene putative oncogen OLIG2 on tissue samples from astrocytomas of different WHO-grades. OLIG2 is a basic helix-loop-helix transcription factor and plays a key role in the differentiation of motoneurons and oligodendrocytes. It also regulates the growth of astrocytes by inhibiting the formation of the p300/STAT3/Smad1 complex, which is crucial for the expression of GFAP, a promoter of the astrocyte differentiation.
Methods: We examined a total of 51 tissue samples of astrocytomas WHO-grade II to IV and first-time recurrent glioblastomas (GBMs) after treatment. All samples were collected after informed consent by our department. OLIG2 expression was detected by semiquantiativ RT Real-Time PCR, using the ABI Sequence Detection System ABI PRISM® 7700 and Qiagen QuantiTect® SYBR® Green PCR Kits.
Results: We found a significantly higher expression of OLIG2 in astrocytomas WHO-grade III compared to all other groups of tumours examined. The mean expression in astrocytomas WHO-grade III was more than three times higher than in astrocytomas WHO-grade II (p=0,026), glioblastomas (p=0,025) and first-time recurrent glioblastomas (p=0,031).
Conclusions: Our results show a significantly higher expression of OLIG2 in astrocytomas WHO-grad III, which points towards a unique function of this gene in this specific grade of glioma. Other groups showed, that a loss of OLIG2 expression causes a higher proliferation of astrocytes. Therefore the reduced expression in our series in the higher grades of tumour might cause the fast growth of these malignomas. The results of our study indicate an involvement of OLIG2 in the increased growth-rate of GBMs and recurrent GBMs compared to astrocytomas WHO-grade III.