20 patients will be included in the study over a 2 year period. Before, during and after treatment we will measure NTX-I, CTX-I, CTX-MMP, bALP, DKK-1, PINP, TRAcP and PTH. NTX, CTX and CTX-MMP are measured to estimate bone degradation. TRAcP is measured to estimate the activity of the osteoclasts. bALP and DKK-1 is measured to evaluate the activity of the osteoblasts and PINP is measured as a marker of new bone formation. PTH is measured in order to evaluate if the positive effects that is observed in bone formation in relations to velcade treatment is due to the pulsative way velcade is administered.