CD44 and breast cancer: In agreement with the in vitro results, organotropic breast cancer cell lines show intense and strong staining for both CD44 (Figure 5C6–C8 in comparison to C5 and Figure 5M6–M8 in comparison to M5) and CD49f (Figure 5C10–C12 in comparison to C9 and Figure 5M10–M12 in comparison to M9).