Serum bone ALP (13.7±6.2 vs 9.3±2.1 ng ml−1, P=0.03 in women with breast cancer and bone metastases and healthy controls, respectively) and serum CTX (0.55±0.56 vs 0.22±0.35 ng ml−1, P=0.0004) were significantly higher in women with breast cancer and bone metastases compared to healthy women. The gene discussed is CYP27A1; the disease is breast cancer.