Total RNA from neurospheres was extracted using the RNeasy Mini Kit (Qiagen). The quality of RNA was assessed using a Bioanalyzer RNA 6000 Nano Chip (Agilent Technologies). The RIN (RNA Integrity Number; Agilent Technologies) values that reflect the integrity of RNA were greater than 8.0 in all the samples. Total RNA was reverse-transcribed, labeled with biotin and hybridized to the Human Genome U133 plus 2.0 Array (Affymetrix, Santa Clara, CA, USA). Hybridization, washing and scanning were conducted according to the manufacturer's instructions. The data analysis was performed using GeneSpring GX (Agilent Technologies). To normalize the inter-microarray range of expression intensities, the percentile shift method (90th percentile) was used. The P-values were calculated using Student's t-test (two-tailed) between data from patient (n=4) and control (n=4) groups. The gene ontology option on GeneSpring GX was utilized to determine the most significant biological processes (corrected P<0.05) represented in the neurosphere transcriptome.
