Figure 3. Verification of circRNA expression using qRT-PCR. (A, B) To confirm the downregulation of four circRNAs observed in circRNA-seq data, hsa_circ_0000915 and hsa_circ_0127664 were found to be downregulated in samples collected from 15 HGG and 15 LGG tissues, and hsa_circ_0001467 and hsa_circ_0008362 were found to be downregulated in 15 HGG tissues and 15 adjacent normal tissues via qRT-PCR. The data are presented as the means ± S.D. of a minimum of 3 independent experiments. *p < 0.05; **p < 0.01; ****p < 0.0001. (C) Head-to-tail splice junctions of 4 circRNAs confirmed by Sanger sequencing. (D) Characterization information for 4 candidate circRNAs. (E) ROC curve analysis of four candidate circRNAs. hsa_circ_0000915 and hsa_circ_0127664 in HGG patients were analyzed against low-grade glioma patients via ROC curves, and hsa_circ_0008362 and hsa_circ_0001467 in HGG were analyzed against normal tissue using ROC curves.