Detection of the cell‐surface epithelial proteins, for example, epithelial cell adhesion molecule (EpCAM) that express in many cancers has been reported to be a strategy to address the problem.18, 19, 20 However, their expression is lost after epithelial‐to‐mesenchymal transition (EMT), a common process by which CTCs lose their epithelial phenotype during cancer progression.21, 22 This leads to the limited sensitivity. Here, EPCAM is linked to cancer.