Abstract B62: Wholesome non-invasive liquid biopsies for pharmacodiagnostic work-up in breast cancer

Abstract

Abstract Background: Diagnosis and treatment of breast cancers is based on histopathological analysis of tumor tissue obtained by invasive biopsies. However invasive biopsies cause pain, anxiety and carry the risk of needle seeding. Though Immunocytochemistry (ICC) profiling of Circulating Tumor Cells (CTCs, defined as EpCAM+, panCK+, CD45-) has been previously attempted for diagnosis, these efforts have been unsuccessful. We used an epigenetically modified medium for enrichment of sufficient viable CTCs. These CTCs were used for diagnosis and characterization. Methods: We obtained 15 ml of venous blood draw from 2500 patients with confirmed diagnosis of breast cancer. CTCs were enriched from PBMCs fraction using an epigenetically acting enrichment process that is lethal towards normal (non-malignant) cells, but confers survival privilege on apoptosis-resistant CTCs. Harvested CTCs were confirmed by immunostaining for EpCAM and pan-CK. Deep ICC profiling of these CTCs was performed with organ specific marker GCDFP15. Theranostic ICC Profiling was performed with ER and Her2. Results: CTCs could be obtained from 2232 samples (89.3%) out of 2500. A subset of 100 samples were characterised by deep ICC profiling, among which 80% of samples were positive for GCDFP15. 14 and 17 samples out of 100 were positive for ER and Her2 respectively. Conclusions: Our results show that ICC based characterization of CTCs can provide necessary diagnostic information non-invasively to substitute conventional procedures dependent on tissue extraction. Citation Format: Dadasaheb Akolkar. Wholesome non-invasive liquid biopsies for pharmacodiagnostic work-up in breast cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr B62.