Fig. 1

circPVT1 is highly expressed in NPC and associated with poor prognosis. A. Schematic representation of the circPVT1 stucture. circPVT1 is 410 nt in length and circularly spliced from exon 2 of the PVT1 gene (RefSeq: NC_000008.11) on chromosome 8q24.21. B. circPVT1 was more stable than the liner PVT1 in NPC cells after RNase R treatment. ***, p < 0.001. C. Intracellular localization of circPVT1 was examined using fluorescence in situ hybridization. Scale bar, 20 μm. D. Expression of circPVT1 was examined in NPC (n = 60) and non-tumor nasopharyngeal epithelial tissues (NPE) (n = 26) by qRT-PCR. Data were represented as mean ± standard deviation (SD). ***, p < 0.001. E. The expression of circPVT1 in correlation with the clinical stages in 26 NPE and 60 NPC samples. **, p < 0.01; ***, p < 0.001. F. Expression of circPVT1 was examined in NPC (n = 159) and non-tumor nasopharyngeal epithelial tissues (NPE) (n = 29) by in situ hybridization; Scale bar: 100 × , 100 μm; 400 × , 20 μm. Left: Representative images of the circPVT1 expression in NPC and NPE tissues. Right: The statistical results of the circPVT1 expression in NPC and NPE tissues. ***, p < 0.001. G. Overall survival (OS) analysis of patients with low and high circPVT1 staining using a Kaplan–Meier curve. H-I. The circPVT1 staining in correlation with the clinical stages (H) and N stages (I) of patients with NPC. *, p < 0.05. I. High circPVT1 expression was associated with distant metastasis in NPC patients. *, p < 0.05