CD44 and breast cancer: We also demonstrated that the CBFB-rich serum exosomes from patients with bone metastasis facilitated the acquisition of metastatic phenotypes by breast cancer cell lines that were hitherto less metastatic or nonmetastatic (Figure 2); these enhanced migration and invasion capabilities were associated with an increased expression of EMT markers, such as Snail, vimentin, and CD44, as well as bone metastasis markers OPN and Runx2.