EpCAM-independent enrichment approach for isolation of circulating tumor cells (CTCs) in breast cancer – What can be found in the EpCAM-depleted fraction?

Abstract

CTCs are essential for establishing metastasis in breast cancer. While many assays currently exist for the enumeration of CTCs, limitations include the reliance on the expression of the cell surface marker epithelial cell adhesion molecule (EpCAM). These approaches may omit CTCs expressing either no/low levels of EpCAM, eventually representing the metastasis-initiating population. In order to successfully capture EpCAM-negative or -low breast cancer cells we have tested different antibodies specific for surface proteins and extracellular matrix (ECM) components for cell lines, spiked samples and blood of metastatic breast cancer patients.