In contrast, Calca expression was not significantly induced in a variety of different cells, including D1 mesenchymal stem cells, BV2 microglia, MLO-Y4 osteocyte-like cells, the breast cancer cell line E0771, primary macrophages and HEK cells, indicating that PTH-induced Calca induction is specific to osteoblasts (Supplementary Fig. 1a, b). This evidence concerns the gene CALCA and breast cancer.