VCAM1 and plasma cell myeloma: Transendothelial migration of human myeloma cell lines in vitro [70] and in vivo [71] and primary MM PCs in vitro [70] could be completely blocked using antibodies against VCAM-1, integrin α4 or integrin β1, suggesting a role for integrin α4β1-VCAM-1 interaction in adhesion to BMECs and subsequent extravasation.