| Objective To investigate the correlation between protein expression of CST6 and bone metastasis in breast cancer, to explore the relationship between osteoporosis and bone clinical parameters with bone metastasis and to build prediction model of bone metastasis, with a view to a prospective treatment for patients, to minimize adverse events and to slow down the process of vicious cycle between osteoporosis and bone metastasis. Methods Immunohistochemistry was used to detect CST6 expression level in cancer and adjacent normal tissue groups. BMD data and clinicopathological parameters of each case were obtained. Statistical analyses were performed to determine their relevance to bone metastasis, to establish bone metastasis prediction model and to test it accuracy. Results ①Positive expression rate of CST6 in bone metastases group is lower than that of the other group, including normal tissue. ② Expression of CST6 is correlated to tumor size, clinical stage and axillary lymph node metastasis. ③ Bone metastasis aggravated osteoporosis, and its effect on osteoporosis is greater than that of age and sex. ④ The bone metastasis in breast cancer is correlated to the expression of CST6, lymph node metastasis, clinical stage, histological grade, expression of HER-2 and ER. Conclusion The positive expression of CST6 in breast cancer is negatively correlated to tumor size, clinical stage, and axillary lymph node metastasis. The reduction of expression level of CST6 and osteoporosis are associated with bone metastases in breast cancer. Clinical stage Ⅲ, histological gradeⅢ, ER and HER-2 expression are major risk factor for bone metastasis in breast cancer. We established breast cancer bone metastasis prediction model, and it can be used clinically to predict the risk of bone metastases in breast cancer patients. |