MAPK11 and breast cancer: MAPK11 activity in breast cancer cells leads to an increased secretion of monocyte chemotactic protein-1, which results in enhanced osteoclastogenesis and bone resorption.28 Therefore, targeting MAPK11 activity could be desirable to not only promote osteoblastogenesis, but also to inhibit osteoclastogenesis and maintain bone integrity at sites of osteolytic bone metastases.