Moreover, receptor interactions such as the intercellular adhesion molecule ICAM-1 expressed on MSC can directly associate with the transmembrane heterodimeric glycoprotein MUC-1 (CD227, DF3, CA15–3) on the cell surface of breast cancer cells to promote an actin-based cell invasive motility in the tumor cells [10–12]. Here, MUC1 is linked to breast cancer.