OBJECTIVETo study the association between the level of serum DKK1 and disease course of multiple myeloma（MM）as well as myeloma bone disease.

METHODSThis study enrolled 145 cases of MM（including 79 newly diagnosed MM, 19 responded MM, 47 relapsed or progressive MM） whose lytic bone disease were evaluated by conventional radiography, ELISA was used to detect the concentration of serum DKK1.

RESULTSSerum DKK-1 elevated in newly diagnosed MM compared with normal donors［2 155（646-35 251）vs 1 487（646-2 577） ng/L, P=0.000］, those responded［1 136（431- 3 582） ng/L, P=0.001］and relapsed/progressive MM［1 695（431-3 582） ng/L, P=0.037］, and the level of relapsed/progressive MM was marginally higher than the responded ones. Moreover, MM patients without lytic lesions in conventional radiography had significantly lower DKK- 1 levels than those with lytic bone disease［1 910（660-26 925）vs 2 519（646-35 251） ng/L, P=0.005］. Notably serum DKK-1 correlated with the number of bone lesions［0 vs 1-3 vs >3 lesions: 1 910（660-26 925）vs 2 155（1 369-5 974）vs 2 547（646-35 251）ng/L, P=0.018].

CONCLUSIONDKK-1 serum concentration correlated with disease course of MM and myeloma bone disease, indicating that DKK-1 was an important factor for the extent of bone disease, which supporting the hypothesis of DKK-1 as a therapeutic target in myeloma bone disease.