Prognostic significance of soluble and ECM associated VEGFA isoforms in high-grade serous ovarian cancer

Introduction: High Grade Serous ovarian cancer (HGSOC) is associated with high rates of mortality in women. Anti- VEGFA therapy (bevacizumab), in combination with chemotherapy, has shown promising results. However, not all patients benefit and side effects can be severe. VEGFA is expressed as a number of isoforms that vary in their affinity for the extracellular matrix (ECM). Preclinical data has suggested measurement of the short, soluble isoform VEGFA121 could be a prognostic and predictive biomarker. Measurement of plasma VEGFA using an ELISA selective for VEGFA121 failed to stratify patients for treatment, in part because plasma measurements do not reflect the quantity and variety of VEGFA isoforms present in the tumour. In light of these results, we hypothesised that high levels of VEGFA121 expression, as measured within the tumour microenvironment may promote HGSOC disease progression and increased sensitivity to bevacizumab