CD44 and cancer: CD44 is a critical adhesion molecule on the surface of 4T1 cells and plays a critical role in the adhesion of metastatic cells to distant sites.37 CD47, a self-marker molecule of 4T1 cells, which is closely associated with tumor aggressiveness through inhibiting phagocytosis of cancer cells by macrophages.38 As shown in Supplementary Fig. 10, 4T1 cell lysates, cell membranes and MSF@CCM, prepared by the same way as MSF@CCM, showed that both CD44 and CD47 marker proteins were retained.