circIFNGR2 was identified as a candidate biomarker for OVCA. (A to I) qRT-PCR was used to detect the relative expression of the nine most downregulated circRNAs in OVCA tissues, circATRNL1, circBNC2, circCLIP2, circCHIPK3, circIFNGR2, circLRCH3, circPCMTD1, circRHOBTB3, and circSETD3. (J) ROC curve of circIFNGR2 in OVCA. (K) qRT-PCR was carried out to check the relative expression of circIFNGR2 in two OVCA cell lines. *P < 0.05, **P < 0.01, ***P < 0.001.