Recent studies show that the abnormalities of dickkopf-1 (DKK-1)are closely related to the bone metastasis and therapeutic effect of breast cancer,prostatic carcinoma,multiple myeloma,neuroblastoma and non-small cell lung cancer.Clinical researches of large sample on the relationships between serum DKK-1 concentration and malignant tumors bone metastases have important clinical significance for evaluating the value of DKK-1 as a clinical biological biomarker of bone metastases and understanding the tumor mechanisms of bone metastases.