Serum Dickkopf-1 acts as a new biomarker in human breast cancer.

BACKGROUND: The serum levels of Dickkopf-1 (DKK1), a secreted Wnt family protein, are different in patients suffering various types of cancers. In the present study, we aim to explore the diagnostic value of DKK1 as a new biomarker in breast cancer. METHODS: Serum was collected from 38 patients with breast cancer and 23 healthy controls. Serological levels of DKK1 were examined by enzyme-linked immunosorbent assay (ELISA). Significance and diagnostic performance including receiver operator characteristic (ROC) and areas under the curve were determined by SPSS software. RESULTS: Serum level of DKK1 was significantly increased in breast cancer patients compared to the healthy controls (P˂0.05). The expression levels of CA15-3 were also evaluated in patients suffering from breast cancer in comparison with healthy controls (P˂0.05). AUC for DKK1 and CA15-3 were 0.81 and 0.64 respectively. Sensitivity and specificity of DKK1 were more than CA15-3 in earlier stage of breast cancer. DKK1 expression in HER-2, estrogen receptor (ER) and progesterone receptor (PR) positive patients was decreased compared with HER-2, ER and PR negative patients. CONCLUSIONS: We found that the expression level of DKK1 in serum was increased in breast cancer patients, suggesting that serum expression level of DKK1 could be a useful biomarker in breast cancer.