EPCAM and neoplasm: The label-dependent method has two selection methods: (1) positive selection, targeting tumor-specific antigens expressed by CTCs, such as epithelial cell adhesion molecules (Ep-CAM), mucin1 (MUC1), or human epidermal growth factor receptor 2 (HER2); and (2) negative selection, targeting antigens expressed by background cells but not by CTCs to remove them, such as CD45 [22].