Circular RNAs (circRNAs) are more stable than linear RNA molecules, which makes them promising diagnostic biomarkers for diseases. By circRNA-sequencing analysis, we previously found that circN4BP2L2 was significantly decreased in epithelial ovarian cancer (EOC) tissues, and was predictive of disease progression. | Ning et al. BMC Cancer 2022 22 6 https s12885-021-09073-z RESEARCH Open Access Plasma circN4BP2L2 is a promising novel diagnostic biomarker for epithelial ovarian cancer Li Ning1 Jinghe Lang2 and Lingying Wu1 Abstract Background Circular RNAs circRNAs are more stable than linear RNA molecules which makes them promising diagnostic biomarkers for diseases. By circRNA-sequencing analysis we previously found that circN4BP2L2 was signifi- cantly decreased in epithelial ovarian cancer EOC tissues and was predictive of disease progression. The aim of this study was to evaluate the diagnostic value of plasma circN4BP2L2 in EOC. Methods Three hundred seventy-eight plasma samples were acquired prior to surgery. Samples were obtained from 126 EOC patients 126 benign ovarian cyst patients and 126 healthy volunteers. CircN4BP2L2 was assessed using reverse transcription-quantitative polymerase chain reaction RT-qPCR . Cancer antigen 125 CA125 and human epididymis protein 4 HE4 were assessed using enzyme-linked immunosorbent assay ELISA . EOC cells were trans- fected with small interference RNAs siRNAs and cell proliferation migration invasion cell cycle and cell apoptosis were performed to assess the effect of circN4BP2L2 in EOC. Receiver operating curve ROC the area under the curve AUC sensitivity and specificity were estimated. Results Plasma circN4BP2L2 was significantly downregulated in EOC patients. Decreased circN4BP2L2 was sig- nificantly associated with advanced tumor stage worse histological grade lymph node metastasis and distant metastasis in EOC. CircN4BP2L2 inhibited tumor cell migration and invasion in vitro. CircN4BP2L2 could significantly separate EOC from benign AUC P Ning et al. BMC Cancer 2022 22 6 Page 2 of 15 RNAs 3 4 . Despite their first discovery in 1976 circR- circN4BP2L2 was significantly downregulated in EOC NAs had been regarded as splicing errors until recent 5 . and was predictive of disease progression 23 . Circ- The rapid .
