EPCAM and hepatocellular carcinoma: In another study, CTCs were found in 28% of HCC patient samples analysed with the CellSearch system but in 100% of samples analysed with an EpCAM‐independent filtration method.43 In a third study, multi‐immunofluorescence identified considerable heterogeneity within CTC populations in HCC patients44 and changes in the ratio of epithelial to mesenchymal cells were associated with a longer time to disease progression.