EPCAM and neoplasm: In 2011, vimentin-positive and cytokeratin-negative CTC clusters were described in three out of six metastatic NSCLC patients [55], and later it was found that circulating tumor microemboli, which were defined as clusters of at least three CTCs, could be observed in 43% of patients using ISET® but were undetectable by CellSearchTM, which captures cells by anti-EpCAM antibodies [39].