CD44 and cancer: Within the TNBC cell lines BT-549 and Hs 578T, there are three different subpopulations [10]: (1) the CD44+CD24− cells characterise the breast cancer stem mesenchymal-like phenotype (cancer stem cells, CSC), (2) the CD44−CD24+ cells are associated with epithelial cells and are largely present in distant metastases [11], and (3) the CD44+CD24+ cells with mesenchymal and epithelial features are plastic and able to self-renew [12].