The use of monocyte- and macrophage-derived vesicles as nanovehicles emphasizes on their ability to evade clearance by the mononuclear phagocyte system and the expression of α4β1 that interacts with the vascular cell adhesion molecule-1 (VCAM-1) of metastatic tumors (8, 40, 41). Here, VCAM1 is linked to metastatic neoplasm.