Genome wide expression profiling identifies specific deregulated pathways in meningioma.

Genome-wide expression signatures improve the understanding of tumor biology. We performed expression profiling of 24 meningioma including 8 of each WHO grade and 2 dura controls analyzing 55.000 transcripts including 18.300 known genes. We compared expression in meningioma vs. dura, expression of low grade (WHO I) vs. higher-grade (WHO II and WHO III) tumors and expression of meningothelial and syncytial meningioma vs. fibroblastic meningioma. Overall expression was significantly decreased in meningioma compared to dura and in meningothelial and syncytial compared to fibroblastic meningioma. Gene expression was exemplarily confirmed by immunohistochemistry using independent samples. Applying our statistical gene set analysis toolkit "GeneTrail", we identified significantly deregulated biochemical pathways using Kyoto encyclopedia of genes and genomes and Transpath databases. Kyoto encyclopedia of genes and genomes pathways with decreased expression in meningioma included cell adhesion molecules (p<0.0001) and cytokine-cytokine receptor interactions (p<0.0001). Pathways with increased expression included several metabolic pathways. Extended expression profiling by a novel statistical gene set enrichment identified pathways that have previously not been associated with meningioma.