Circular RNA profiling reveals circRNA1656 as a novel biomarker in high grade serous ovarian cancer.

Circular RNA (circRNA) is a class of endogenous non-coding RNAs that are closely related to the pathogenesis of many human diseases, particularly cancer. However, the characterization of circRNAs in high-grade serous ovarian cancer (HGSOC) remains unknown. This study aimed to investigate the expression profile of circRNAs in HGSOC. Expression profiles of circRNAs differential expression based on circRNAs High-throughput sequencing were identified in 3 HGSOC specimens and 3 normal ovarian tissues. A total of 710 differentially expressed circRNAs were found (354 expressions up-regulated and 356 expressions down-regulated). CircRNA sequencing data were verified by qRT-PCR in HGSOC tissue and benign ovarian lesions. Differential expression of 7 circRNAs (circRNA385, circRNA2058, circRNA3336, circRNA2606, circRNA1656, circRNA1312 and circRNA7474) in HGSOC tissue was confirmed by qRT-PCR. Among them, circRNA1656 showed the highest fold change. qRT-PCR was used to verify the expression of circRNA1656 in ovarian cancer cell lines. In order to analyze the relationship between circRNA1656 expression and clinical pathological biological characteristics of HGSOC, qRT-PCR was used to verify the expression of circRNA1656 in 60 HGSOC tissues compared with 60 benign ovarian lesions. The expression of circRNA1656 was down-regulated in HGSOC tissues and ovarian cancer cell lines, and correlated with the FIGO stage of HGSOC. circRNA1656 has the potential to serve as a novel tumor marker for HGSOC.