Serum circSETDB1 is a promising biomarker for predicting response to platinum-taxane-combined chemotherapy and relapse in high-grade serous ovarian cancer

Purpose: Circular RNAs (circRNAs) are emerging as promising biomarkers for various human malignancies. However, the application of circRNAs as non-invasive biomarkers in high-grade serous ovarian cancer (SOC) remains to be elucidated. Here, we aim to investigate the feasibility of using serum circSETDB1, a tumor-promoting circRNA generated from the SET domain bifurcated histone lysine methyltransferase 1 (SETDB1), known to be upregulated in SOC, as a biomarker for detecting SOC progression, predicting relapse, and evaluating the effectiveness of SOC treatment. Methods: Serum circSETDB1 levels were measured using quantitative real-time RCR in 60 SOC patients (18 primary chemoresistance, 42 primary chemosensitive) and 60 healthy volunteers. Progression-free survival curve was calculated by Kaplan-Meier analysis. Diagnostic value was analyzed using receiver operating characteristic curve (ROC) method. Results: Serum circSETDB1 expression is upregulated in SOC patients. Higher levels of circSETDB1 are positively associated with advanced clinical stage, lymph node metastasis of SOC patients. Notably, serum circSETDB1 levels are significantly increased in primary chemoresistance patients. Patients with higher levels of circSETDB1 have a shorter progression-free survival time. In addition, diagnostic value analyses revealed that serum circSETDB1 can distinguish patients with SOC from healthy volunteers as well as patients with primary chemoresistance from those with primary chemosensitivity. Conclusion: Our data suggest that serum circSETDB1 may serve as a novel non-invasive biomarker for detecting SOC progression and predicting response to chemotherapy and relapse in high-grade serous ovarian cancer.