ALDH1A1 and cancer: We found that tumors formed by sh-AhR + sh-Aldh1a1 CD133+ cells were similar in weight (Fig. 7a) and volume (Fig. 7b) than those produced by sh-AhR CD133+ cells, suggesting that a reduction in the number of cancer stem-like cells could be the most likely factor compromising tumor growth by Aldh1a1 depleted AhR + sh-Aldh1a1 cells.