In this system, CTCs are detected as epithelial cell adhesion molecule (EpCAM)/cytokeratin-positive cells in the blood; however, it is difficult to detect CTCs undergoing epithelial-mesenchymal transition (EMT) by the CellSearchTM System, because EpCAM expression declines on tumor cells undergoing EMT [5–7]. This evidence concerns the gene EPCAM and neoplasm.