USP15 and glioblastoma: Evaluation of gene copy number aberrations of USP15 in GBM revealed a deletion frequency of 10.9% (95% exact confidence interval [CI] 4.5-21.2) for our GBM dataset (NCH-EORTC, n= 64, human methylation 450K BeadChip) which was corroborated in the GBM dataset of The Cancer Genome Atlas (TCGA) with a deletion frequency of 10.8% (95% [CI] 8.0-14.2) and an amplification frequency of 1.2% (95% CI, 0.4-2.8) (n=415, ACGH-244k) [2].