Quantification and molecular characterization of circulating epithelial tumor cells (CETC) for determination of their metastatic potential.

Abstract

e13585 Background: In breast cancer predictive markers for therapy are derived from the primary tumor but systemic therapy aims at eliminating the remnant tumor cells which are left in the body after surgery, part of which are the cells circulating in peripheral blood. In the future, it will become mandatory for individualized therapy to better characterize this remnant disease for targeted therapeutic approaches. Methods: From peripheral blood from each of 50 newly diagnosed breast cancer patients after surgery up to 100 vital circulating epithelial-antigen positive cells were isolated using an automated capillary cell isolation system (MMI CellEctor) and deposited individually into wells of Ampli Grid slides (Advalytics-Beckman, Munich) under visual control. The mRNA was reverse transcribed and amplified using primers for 6-15 different tumor associated target genes among them EpCAM and HER2/neu. Results: Expression profiling could be successfully performed from more than 80% of all individually deposited isolated cells demonstrating the epithelial nature of these cells. Cells of individual patients showed heterogeneity with respect to different genes. Expression profiling of the population of individually deposited circulating epithelial cells from breast cancer patients can now be compared to the profile of the primary tumor and correlated to the clinical course of disease Conclusions: Further analysis by high through-put profiling of the remnant tumor burden in breast cancer patients after surgery comprising the cells circulating in peripheral blood may contribute to better characterize the targets of systemic therapy in order to individualize cancer therapy.