miRNA expression profile is related to vestibular schwannoma growth rate

Tumor miRNA expression is related to the growth rate of sporadic vestibular schwannomas. Rapid tumor growth is associated with deregulation of several miRNAs, including up-regulation of miR-29abc, miR-19, miR-340-5p, miR-21 and miR-221 and down-regulation of miR-744 and let-7b. Gene ontologies affected by the deregulated miRNAs included neuron development and differentiation, gene silencing and negative regulation of various biological processes, including cellular and intracellular signalling and metabolism. We used microarray to determine the miRNA expresison in vestibular schwannoma their relation to the growth rate. Tumor tissue was sampled during surgery of patients with a sporadic vestibular schwannoma. Tumor growth rate was determined by tumor measurement on the two latest pre-operative MRI scans. Tumor miRNA expression was analysed using the Affymetrix Gene Chip® protocol, and CEL files were generated using GeneChip® Command Console® Software and normalized using Partek Genomics Suite 6.5. The CEL files were analyzed using the statistical software program R. Principal component analysis, affected gene ontology analysis and analysis of miRNA expression fold changes were used for analysis of potential relations between miRNA expression profile and tumor growth rate.