CellSearchenriches CTCs using magnetic particles containing antibodies againstthe Epithelial Cell Adhesion Molecule (EpCAM) (also known as CD326).EpCAM is a cell-surface glycoprotein that is known to be highly expressedin epithelial carcinomas, including breast cancer and prostate cancer.8 However, the clinical use of CTCs is limitedby their scarcity in the peripheral blood (1 CTC/105–6 blood cells).9 This evidence concerns the gene EPCAM and breast cancer.