CD44 and breast cancer: The foremost report on the identification of CSCs in breast cancer [13] based on the expression of the antigenic phenotype CD44+/CD24−/EpCAM+/lin− is not a universal representation of tumor-initiating cells (TICs) across all breast cancer subtypes but highlights a heterogeneous mix of normal mammary cells committed to a distinct epithelial–mesenchymal transition (EMT) program [40].