Multiple myeloma (MM) is a cancer that affects preferentially the bone marrow (BM). Precise knowledge of the mechanism(s) mediating lodging of tumor cells in the BM and their proliferation in that organ may lead to new therapies that could block tumor progression. Another promising therapeutic approach is the generation of specific T lymphocytes that kill MM cells. We will dissect in vivo the molecules responsible for MM cell recruitment to and traffic within the BM. We will also generate T cells able to migrate from blood to BM and to kill tumor cells. We will characterize how these T cells interact with MM in the BM of living mice.