Angiogenesis and Ovarian Cancer: What Potential Do Different Subtypes of Circulating Endothelial Cells Have for Clinical Application?

Ovarian cancer (OC) remains the most fatal disease of gynaecologic malignant tumours. The neovasculature in the tumour microenvironment principally comprises endothelial cells. Haematogenous cancer metastases are significantly impacted by tumour neovascularisation, which predominantly depends on the tumour-derived endothelial vasculogenesis. There is an urgent need for biomarkers for the diagnosis, prognosis and prediction of drug response. Endothelial cells play a key role in angiogenesis and other forms of tumour vascularisation. Subtypes of circulating endothelial cells may provide interesting non-invasive biomarkers of advanced OC that might have the potential to be included in clinical analysis for patients' stratification and therapeutic management. In this review, we summarise the reported studies on circulating endothelial subtypes in OC, detailing their isolation methods as well as their potential diagnostic, prognostic, predictive and therapeutic utility for clinical application. We highlight key biomarkers for the identification of circulating endothelial cell subtypes and their targets for therapies and critically point out future challenges.