POU5F1 and cancer: Consistent with the effects of CAF-derived exosomes, circ_0067557 overexpression reduced apoptosis (Fig. 4F) and promoted cancer stem cell (CSC) features (CD133, CD44, and OCT4 protein expression) (Fig. 4G, H) in HCT116 cells, while circ_0067557 knockdown caused the opposite effects.