Fig. 3

Circulating tumor cells show the molecular and functional features of cancer stem cells. A Typical cancer stem cell (CSC) antigens as CD44, CD105, CD90 and CD73 were highly expressed by CTC-AT in a fashion similar to Sk-Mel-28 positive control. B Representative panels showing ALDH1 activity in presence (+) or absence (−) of an ALDH1 inhibitor (DEAB). Cells included in the framed region are those ALDH1⁺. C mRNA expression levels of CSC transcription factors in CTC-AT cells and Sk-Mel-28. Results are expressed as 2^−Δct and bars are mean ± SEM. **p < 0.01. D) Melanospheres formation efficiency of the three generation (G1-G3) of CTC-AT. Data are mean ± SEM (n = 3). SFA: sphere formation assay. Each experiment was performed in triplicate, and representative examples are shown