Delayed diagnosis of ovarian cancer (OC) is usually a cause of its high mortality. OC counts for one of the most aggressive gynecological malignancies. Noninvasive biomarkers may be used to help with diagnostic and treatment decisions in OC management. The incidence and clinical significance of occult OC cells (circulating tumor cells-CTCs) in the peripheral blood of patients with newly diagnosed or nondiagnosed OC at the time of surgical intervention were examined in our study. The objective of the study was to isolate and cultivate CTCs in OC patients (mainly stage IIIB-C) by a recently introduced size-based separation method (MetaCell(®)). CTCs were successfully isolated in patients with OC capturing cells with proliferation potential. The cells were enriched in good fitness, which enabled the short term in vitro culture of the CTCs. The CTCs may be used for further downstream applications (e.g. gene expression analysis) even if in the majority of the in vitro CTC cultures no confluence was reached. The CTCs were detected in 77 out of 118 patients (65.2%). CTC positivity was given to the relationship with different disease stage parameters with special focus on CA125 marker levels. The results show that the information on CTC presence may provide new and independent prognosis staging information to the patient description. Several interesting relationships of CA125, age and ascites presence are reported. As shown in our patient sample, patients with ascites tend to have higher CA125 levels, even if the CTCs were not found in the peripheral blood. It suggests that hematogenous dissemination is fully represented by the CTCs while lymphogenic dissemination is represented by elevated CA125. In this context, easy access to CTCs provided by the method applied in our study, both at the time of diagnosis and relapse, may become an increasingly valuable tool in future. This methodology may provide an opportunity for more personalized medicine where treatment for OC may be guided by information from an individual's CTC molecular profile.

Department of Cell and Molecular Biology 3rd Faculty of Medicine Charles University PragueRuska 87 100 97 Prague Czech Republic

Department of Gynecology and Obstetrics University Hospital Kralovske Vinohrady Srobarova 50 100 34 Prague Czech Republic

Department of Histology and Embryology Wroclaw Medical UniversityWrocław Poland

Department of Laboratory Genetics University Hospital Kralovske Vinohrady Srobarova 50 100 34 Prague Czech Republic

Department of Laboratory Genetics University Hospital Kralovske VinohradySrobarova 50 100 34 Prague Czech Republic

Department of Pathology Masaryk's Hospital in Usti nad Labem Krajska zdravotni a s Socialni pece 3316 12A 40113 Usti nad Labem Czech Republic

Division of Surgical Oncology Gynaecological Oncology Chemotherapy and Department of Oncology Wroclaw Medical University Plac Hirszfelda 12 53 413 Wrocław Poland

Division of Surgical Oncology Gynaecological Oncology Chemotherapy and Department of Oncology Wroclaw Medical UniversityPlac Hirszfelda 12 53 413 Wrocław Poland

Lower Silesian Oncology CentreWroclaw Plac Hirszfelda 12 53 413 Wroclaw Poland