The mechanisms involved in the growth of multiple myeloma and the development of myeloma bone disease are not fully understood. We have found that a newly discovered molecule known as LIGHT is decreased in patients with multiple myeloma. The aim of the present proposal is to determine the role of LIGHT and an associate molecule, decoy receptor 3, in the growth of myeloma cells in the bone marrow and in the development of myeloma bone disease. We anticipate that this will lead to an increased understanding of how myeloma cells grow and identify new ways to treat this disease.