EpCAM-negative cancer–associated circulating cells (CACS) in blood samples of women with triple-negative breast cancer (TNBC).

Abstract

e11559 Background: Breast circulating tumor cells (CTCs) are commonly isolated by positive selection enrichment targeting the epithelial cell adhesion activating molecule, EpCAM. The accepted definition of CTCs is cells that have: 1) nuclei, 2) cytokeratin, 3) EpCAM and that these cell are negative for the pan-hematopoeitic marker CD45. Recent data suggests that other rare circulating cells (CACs) are present in the blood of metastatic cancer patients including CD45+ cytokeratin+ cells (Toner, 2010). It is hypothesized that these cells are tumor cells of a different phenotype or that are interacting with or ingested by hematopoeitic cells. We aimed to evaluate CACS in TNBC using a negative depletion technology. Methods: Ten women with metastatic triple negative breast cancer were enrolled. Blood was processed using previously described immunomagnetic negative depletion (Jatana et al. 2010; Yang et al. 2009). Multiparameter, flow cytometry analysis was conducted prior to, and after depletion of CD45 cells....