Gene expression data from pilocytic astrocytoma tumour samples and normal cerebellum controls

Pilocytic astrocytomas (PA) are the most common brain tumor in pediatric patients and can cause significant morbidity, including chronic neurological deficiencies. They are characterized by activating alterations in the mitogen-activated protein kinase (MAPK) pathway, but little else is known about their development. To further define their molecular development, we analysed the global DNA methylation profiles of 61 PAs and 6 normal cerebellum samples and integrated this data with transcriptome profiling. These data revealed two subgroups of PA that separate according to tumor location (infratentorial versus supratentorial), and identified key neural developmental genes that are differentially methylated between the two groups. Significant expression differences were identified for the majority of differentially methylated genes, and these were unexpectedly associated with a strong positive correlation between methylation and expression. We also identified a large number of differentially methylated/expressed genes between cerebellar PAs and normal cerebellum, which included additional developmental genes.

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Lambert SR, Witt H, Hovestadt V, Zucknick M, Kool M, Pearson DM, Korshunov A, Ryzhova M, Ichimura K, Jabado N, Fontebasso AM, Lichter P, Pfister SM, Collins VP, Jones DT