Liquid biopsy-based diagnostic evaluation of hypermethylated CpG sites for ovarian cancer diagnosis

Ovarian cancer is a heterogeneous gynaecological malignancy characterised by high mortality and an absence of reliable biomarkers for detection. In this study, a CpG-specific, ARMS-PCR approach was employed to evaluate the methylation status of six diagnostically relevant CpG sites in 65 epithelial ovarian cancer tissues and 35 healthy controls. Based on methylation frequency, the top three CpG sites were selected and evaluated in two diagnostic panels. A TaqMan-based MethyLight assay incorporating cg02957270, cg00480298 and Col2A1 (as endogenous control) was developed for tissue and serum cell-free DNA cohort analysis. ARMS-PCR demonstrated diagnostic sensitivities of 80%, 73.3% and 82.3% for singleplex and multiplex panels, respectively. However, the multiplex MethyLight assay achieved 86% sensitivity and 90% specificity, with an AUC of 0.97 in the serum cohort. Furthermore, while ARMS-PCR panels displayed limited clinicopathological correlations, MethyLight showed significant correlations (P < 0.05). Overall, this pilot study highlights the promise of liquid biopsy-based diagnostics using independent hypermethylated and hypomethylated CpG biomarkers for ovarian cancer detection.