DCN and breast cancer: To our knowledge, we are the first laboratory to extend these findings to bone metastatic breast cancer, whereby we discovered a subpopulation of osteoblasts called “educated osteoblasts” (Figs. 1, 2, and 5) that reduce breast cancer proliferation (Fig. 6) and entry into the S phase of cell cycle (Fig. 7), in part via the proteins NOV and decorin (Figs. 9 and 10).