Introduction/Background .Over the past decade, the concept of 'liquid biopsies' has been introduced as an alternative to conventional tissue examination for cancer. Advantages of this approach include potentially earlier warning of treatment resistance or new mutational changes as cancer progresses and the significantly greater acceptability of repeated testing for patients. In this study, we report detection of non-haematopoietic circulating cells (CCs) from patients participating in the Rare Neoplasias of Gynaecological Origin (RaNGO) study. This is a UK study designed to demonstrate the feasibility of collecting accessible information about specified rare gynaecological cancers, to facilitate in-depth studies of their clinical and biological behaviours leading to a greater understanding of mechanisms of disease progression and response to treatment, possibly also applicable to common tumours. It includes the development of a tissue bank, with appropriate patient consents for suitable ethically approved translational research projects. Patients with advanced stage rare gynaecological tumours are also eligible to donate blood for the evaluation of potential circulating biomarkers

Methodology Venous blood was collected prospectively from 3 patients diagnosed with either FIGO stage IIIc squamous cell carcinoma (SCC) arising from a dermoid, adult granulosa cell tumour (GCT), or small cell cancer of the ovary cancer (SCOC). All patients were on active (palliative) treatments for their inoperable malignancies. CCs were evaluated using ImageStream Technology^TM and specific antibodies to differentiate epithelial from haematopoetic cells.

Results Significant numbers of CCs determined by being CK⁺/CD45^- were detected in all 3 patients. Numerically, 195, 750 and 60 per millilitre of blood for SCC, GCT and SCOC respectively.

Conclusion This is the first study to demonstrate that liquid biopsies might have a role in a number of different rare gynaecological malignancies. Future studies will concentrate on CC characterisation using multiple antibodies and enumeration from sequential samples in relation to treatment.

Disclosure Nothing to disclose