CD44 and breast cancer: The mRNA expression levels of CSC-related genes CD44, ZEB1, and SNAI1, and the cell surface expression level of CD44 were significantly lower when breast cancer PDX cells were cocultured with Cfd-KO mADSCs than when cocultured with WT mADSCs; and were recovered when HGF was added to the culture medium (Supplementary Figure S1).