Michigami et al. used the α4β1 (VLA-4) positive murine myeloma cell line 5TGM1 and mouse marrow stromal cell line ST2, which expresses VCAM-1, to show that the interaction of myeloma cells with stromal cells via α4β1-integrin/VCAM-1 produces osteoclastogenic activity, suggesting that the presence of stromal cells provide a microenvironment for exclusive colonization of myeloma cells in the BM [12]. The gene discussed is VCAM1; the disease is plasma cell myeloma.