Introduction/Background*Routine blood markers provide poor diagnostic capacity for ovarian cancer. Ultrasound examination using the criteria developed by International Ovarian Tumor Analysis group is the most sensitive and specific diagnostic method, but in up to 20% of cases evaluation is inconclusive (Sladkevicius et al. 2020; Valentin et al. 2011). We pioneered platelet proteome analysis and identified platelet biomarkers of ovarian cancer (Lomnytska et al. 2018).

Methodology The purpose of the study is to identify diagnostic marker panel on platelet microvesicles in blood plasma for non-invasive differential diagnostics of benign adnexal lesions, borderline tumours and ovarian cancer. The expression of platelet protein biomarkers on platelet microvesicles in patients with benign and malignant adnexal lesions was analysed using flow cytometry. Identified biomarker panels were analysed together with the gynaecologic ultrasound criteria.

Result(s)*Analysis comprised 39 patients with benign adnexal lesions (n=10), borderline (n=10), ovarian cancer stage I-II (n=8) and stage III-IV (n=11). Using flow cytometry analysis of platelet microvesicles in platelet-poor blood plasma, we detected our previously identified by proteome analysis of platelets markers ACTN4, CRKL, ERP29, GELS, PHB and SRC (Lomnytska et al., 2018). Expression of P-selectin positive platelet microvesicles was 2-fold higher in ovarian cancer (p<0.05). Increased expression of our identified markers on P-selectin positive platelet microvesicles was observed in ovarian cancer (figure 1).

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Abstract 464 Figure 1

Conclusion*Identified platelet biomarkers (Lomnytska et al. 2018) are detectable on platelet microvesicles in blood plasma with increased expression in ovarian cancer. Further analysis of microvesicles in relation to ultrasound evaluation has the potential to improve ovarian cancer diagnostics.