PO70COMPARISON OF THE TRANSCRIPTIONAL LANDSCAPES OF POSTERIOR FOSSA EPENDYMOMA ACROSS AGE GROUPS

Abstract

INTRODUCTION: Ependymomas are rare glial tumors of the brain and spinal cord. Although common in children, posterior fossa (PF) ependymomas occur at any age and show marked clinical differences between children and adults. To better understand the biological basis for these observations, we performed a comparison of the expression profiles of PF ependymoma across age groups. METHOD: Our study included expression profiles of tumor samples from PF of 37 ependymoma patients with age ranging from 1 to 63 years. The change in gene expression among infants (0-3 years), children (4-17 years), and adults (≥18 years) was calculated using linear models based on Bayesian moderated statistics. RESULTS: We detected a total of 613 genes that show high expression levels in infants (adjusted P value, FDR < 0.05) and 444 genes in adults. In contrast, there was no significant gene expression alteration detected in Children. Similar trend of expression alterations was observed in an independent data set of 34 PF ependymomas (960 genes for infants; 434 for adults; and 1 gene for children). The infant PF ependymoma was enriched for genes associated with axon guidance, cell adhesion, ECM-receptor interaction, calcium, chemokine, MAPK, Neurotrophins, PPAR signaling pathways, whereas the adults were significantly enriched for genes associated with cilium organization and microtubule-based process. Markers of ECM signaling (LAMA2, log2 fold change (FC) = 2.82, FDR < 0.009; CD44, FC = 1.98, FDR < 0.007) were overexpressed in infants, while NELL2 (FC = 1.99, FDR < 0.002) was overexpressed in adult PF ependymomas. CONCLUSION: Our results showed substantial differences in gene expression landscapes underlying different age groups of PF ependymoma.