CD44 and breast cancer: IL-8 enhanced stemness gene expression of ALDH−CD44− cancer cells, while CXCR1 antibody treatment exerted the opposite effect on PDK4-overexpressing ALDH−CD44− cells, suggesting a potential regulatory role of IL-8 in PDK4-modulated stemness in ovarian cancer, consistent with data obtained from a previous study supporting the utility of IL-8 as a therapeutic target to diminish CSC activity in breast cancer.42 Blockade of the NF-κΒ pathway by DMAPT could suppress sphere-forming capacity and stemness gene expression in ALDH+CD44+ or PDK4-overexpressing ALDH−CD44− cells.