Circulating Osteocalcin-positive Cells in Breast Cancer Bone Metastasis

Bone metastasis (i.e. cancer cell spreading to bone) is the major clinical problem of advanced breast cancer patients. Bone metastasis is not curable nor preventable. Currently available therapeutic approaches are only palliative. The major hurdle for improving bone metastasis treatment is lack of sensitive diagnostic tools. Diagnosis of bone metastasis is heavily dependent on radiographic imaging of bone destruction that are detectable only when the lesion is significantly large. Accordingly, if bone metastasis can be detected at an earlier time point when bone destruction is minimal or incipient, treatments can be given earlier and the patients can expect better outcomes. We and others previously have found that a subset of bone-forming cells (i.e. circulating osteocalcin-positive cells) exists in the blood stream of the patients with bone diseases (e.g. bone metastasis and inflammation) or active bone formation (e.g. adolescence) in mouse models anf human samples. Extended from this laboratory observation, this clinical study proposes to test the hypothesis that circulating osteocalcin-positive cells are the early biomarker of breast cancer bone metastasis. For this aim, this study will measure circulating osteocalcin-positive cells in the blood samples of breast cancer patient, and examine whether the measure sensitively detects bone metastasis.