Because E2F4 and the DREAM complex are known to modulate the transcription of several genes involved in cell-cycle regulation [26, 27], and because previous studies reported E2F4 to play, alternatively, a positive or a negative role on cell proliferation depending on specific experimental systems [28], we decided to test whether E2F4 down-regulation would translate in a functional perturbation of the proliferative capacity of EpCAM+/CD44+/CD166+ (CSC-enriched) cancer cells at baseline (i.e., in the absence of chemotherapy). Here, CD44 is linked to cancer.