The two groups of gliomas exhibited very different gene expression profiles and were consistently distinguished by unsupervised clustering analysis.
One of the most striking differences was the expression of normal brain genes by oligodendrogliomas with 1p19q codeletion.
These gliomas harbored a gene expression profile that partially resembled the gene expression of normal brain samples, whereas gliomas with EGFR amplification expressed many genes in common with glioblastoma cancer stem cells.
The differences between the two types of gliomas and the expression of neuronal genes in gliomas with 1p19q codeletion were both validated in different series.
Immunohistochemical study of the most differentially expressed neuronal gene, alpha-internexin, clearly differentiated the two groups of gliomas, with 1p19q codeletion gliomas showing specific staining in tumor cells. (18492260)
IDH1 mutations
In homogeneously treated groups of anaplastic oligodendroglioma patients, the presence of IDH1 mutations was found to carry a very strong prognostic significance for OS but without evidence of a predictive significance for outcome to PCV chemotherapy. (20160062)
IDH1 mutations are strongly associated with 1p/19q codeletion and MGMT promoter methylation.
References
IDH1 and IDH2 mutations are prognostic but not predictive for outcome in anaplastic oligodendroglial tumors: a report of the European Organization for Research and Treatment of Cancer Brain Tumor Group. van den Bent MJ, Dubbink HJ, Marie Y, Brandes AA, Taphoorn MJ, Wesseling P, Frenay M, Tijssen CC, Lacombe D, Idbaih A, van Marion R, Kros JM, Dinjens WN, Gorlia T, Sanson M. Clin Cancer Res. 2010 Mar 1;16(5):1597-604. PMID: 20160062
Anaplastic oligodendrogliomas with 1p19q codeletion have a proneural gene expression profile. Ducray F, Idbaih A, de Reyniès A, Bièche I, Thillet J, Mokhtari K, Lair S, Marie Y, Paris S, Vidaud M, Hoang-Xuan K, Delattre O, Delattre JY, Sanson M. Mol Cancer. 2008 May 20;7:41. PMID: 18492260 [Free]
