Dickkopf-1 expression as a predicting factor for bone metastasis in breast cancer

Bone is the main metastatic site in breast cancer patients. A marker is needed for early identification of breast cancer patients who are at risk of bone metastasis. Dickkopf-1 (DKK-1) plays an early role in the cascade of bone metastasis process in breast cancer. Therefore, detection of its expression is presumed to predict bone metastasis better than other biomarkers. This study was aimed to determine the potential of DKK-1 expression as a predictor of bone metastasis in breast cancer and its association with clinicopatho-logical factors. The study design was a retrospective cohort study of medical records in the Surgical Oncology Division, Department of Surgery, Cipto Mangunkusumo General Hospital, Jakarta, Indonesia from October 2018 to June 2019. Bivariate analysis was performed to analyse data using Chi square test or Fischer’s exact test. We included 76 subjects divided into two groups: bone metastasis group (n= 38) and non-bone metastasis group (n=38). The H-Score cut-off value for DKK-1 expression was 142.5. We found a statistically significant association between high expression of DKK-1 and the incidence of bone metastasis in breast cancer (odd ratio [OR]= 12.083, 95% confidence interval [CI]= 4.101-35.600, p< 0.001). Associations between DKK-1 expression and clinico-pathological factors were not statistically significant. DKK-1 expression is potential to predict and an independent factor of the bone metastasis occurrence in breast cancer.