Co-expression of Cytokeratin, ALDH1 and TWIST in cancer cell lines and a single CTC detected in a breast cancer patient, ARIOL system. Triple immunofluorescence was performed in cytospin preparations using anti-CK (green), anti-ALDH1 (orange) and anti-TWIST (pink) antibodies. Cell nuclei were stained with Dapi (blue). A) HepG2 control cells and three representative breast cancer cell lines, ARIOL system (x400). B) A CTC (ALDH1high/TWISTnuc phenotype) detected in a metastatic breast cancer patient, ARIOL system (x200).