TCG2, TCG3 and TCG4 tumor characterization for oncogenic alterations commonly found in high-grade gliomas.

1Primary diagnoses (determined in 2001 by a first pathologist according to the WHO classification 2000) were compared to a second opinion (given by an independent pathologist in 2013 according to the WHO classification 2007). AO = anaplastic oligodendroglioma. 2EGFR amplification was assessed using CGH array and FISH, leading to consistent results. 3The expression of the EGFR variant III was determined by western-blotting. 4EGFR protein overexpression was assesed by immunohistochemical detection and compared to non tumor tissue. 5Phospho-EGFR expression level was determined using the Bio-plex phosphotrein arrays. 6PTEN status was investigated using three techniques: CGH array, qRT-PCR and protein expression analysis by western-blotting, leading to consistent results. (-) = PTEN loss. 7PIK3CA mutation analysis (exons 9 & 20) was performed using direct sequencing. 8IDH1 mutation was assessed by immunohistochemistry; 91p/19q Codeletion was determined using microsatellite analysis for loss of heterozygosity on chromosome 1 and 19q, as previously described. In parallel, IHC studies showed no expression of alpha-internexin. 10p53 status was determined by FASAY and confirmed by IHC: WT = wild type or MUT = Mutated. 11MGMT promotor methylation status was evaluated with the methylation specific polymerase chain reaction after DNA modification by sodium bisulfite: M = mutated or U = unmethylated.