The interaction of very late antigen 4 (VLA-4), vascular adhesion molecule (VCAM), leukocyte function-associated antigen 1 (LFA-1), and intercellular adhesion molecule 1 (ICAM-1) with bone marrow stromal cells induces primary multidrug resistance in vitro and in vivo in multiple myeloma cells [75]. Here, ICAM1 is linked to plasma cell myeloma.