CD44 and breast cancer: To compare the expression of cancer stem/progenitor cell-like marker protein in the 10AT-Her2 cell population with other well-established human breast cancer cell lines, protein levels of nucleostemin, CD44, ALDH-1 and CD24 were assessed in 10AT-Neo, 10AT-Her2, MCF-7, MDA-MB-231 and SKBR3 cells (Figure 2C).