Multiple myeloma is a B cell neoplasm characterized by clonal expansion of malignant plasma cells in the bone marrow with frequent occurrence of lytic bone disease. Osteolysis result from unbalanced bone turnover with enhanced resorption related to increased osteoclast recruitment and activity and low bone formation. The osteoblasts are the cells responsible of bony matrix deposition. We would study the mechanism/s and the eventual defects in osteoblast differentiation pathway that inhibits the physiological coupling between bone resorption and formation.