Introduction/Background Ovarian cancer is the leading cause of death among gynaecological cancers. This is mainly due to the late diagnosis where most patients are diagnosed in advanced stage because of lack of symptoms in early stage. Additionally, there is a clinical problem in differentiating between benign and malignant adnexal lesions. This study aims to elucidate whether there is a difference between benign, malignant and borderline adnexal lesions in expression of platelet protein biomarkers in extracellular vesicles.

Methodology We collected blood samples prior to planned surgery from 75 patients with benign, borderline, stage I-II and stage III-IV ovarian cancer, respectively. Collected from peripheral venous blood, citrate plasma was subjected to double centrifugation prior to analysis of platelet extracellular vesicles using flow cytometry. In earlier proteomics study several potential biomarkers in platelets were discovered, therefore we used specific antibodies in the flow cytometer. For statistical analysis Kruskal-Wallis test, Mann-Whitney U test and ROC-curves were used.

Results Preliminary results show that there is a stronger expression of platelet antibodies in extracellular vesicles in patients with malignant than in benign adnexal lesions. There is also a different expression of tumour markers in platelet extracellular vesicles in malignant compared to benign adnexal lesions. In particular, Gelsolin (GSN), has a strong expression in ovarian cancer stage IIIB-IV compared to both patients with benign adnexal lesions and patients that received neoadjuvant chemotherapy prior to the blood test and surgery, with an AUC of 0.875 (p<0.001) and 0.923 (p<0.001) in platelet free plasma, respectively. With Kruskal-Wallis test same comparisons generates a X2 value of -20.3 (p=0.029) and -25.3 (p=0.008).

Conclusion In ovarian cancer there is a platelet activation which is possible to analyse with flow cytometry and therefore a potential method for differentiating between different adnexal lesions in clinical practice.

Disclosures Nothing to declare.