EPCAM and neoplasm: When the CTCs isolating and enriching method improves to obtain sufficient numbers of CTCs, people might confirm if the discrepancies in the mutation statuses between tumor/metastatic tissues and CTCs are caused by the subcolonies and heterogeneity in bulk tumor tissue.16, 47 Third, the CTCs isolation technologies, including Cell Search, which is based on EpCAM, may have substantial limitations.48, 49 Many studies conclude that primary tumor cells should undergo epithelial-to-mesenchymal transition (EMT) to invade the blood vessels, which accelerates the production of CTCs.