Breast cancer cells can express receptor activator of NF-κB ligand (RANKL), parathyroid hormone-related protein (PTHrP) and interleukins to activate osteoclast directly and indirectly, leading to enhanced osteoclastic bone resorption, which in turn release active transforming growth factor-beta (TGF-β) and other cytokines to promote breast cancer growth3, 4, 5. Here, PTHLH is linked to breast cancer.