Recent reports have suggested that inhibition of RANK ligand (RANKL) – essential in the development of osteoclasts – may also play a role in the management of proliferative breast disease, and that inactivation of the RANK receptor in the mammary epithelium can result in decreasing cases of medroxyprogesterone acetate mammary cancer. Breast Cancer Research has published two viewpoint articles that explain how and why these results are important in controlling this form of breast cancer.
In separate articles, Dr Russ Hovey, University of California Davis, USA, and Dr Cathrin Brisken, Swiss Institute for Experimental Cancer Research, Switzerland, analyse the findings of both reports, and agree that RANK and RANKL may have a key role in the development of mammary-gland cancer. Dr Hovey further explains that other proliferative pathways in mammary glands downstream of RANK may effect, among other events, hormones and growth factors. This has important implications as prolactin and parathyroid hormone-related peptide can develop RANKL in the mammary glands.
Dr Brisken also questions whether a recent FDA-approved RANKL-inhibiting drug used to treat osteoporosis could be also used in the treatment of breast cancer, especially as RANKL has been found to be expressed in 11% of human tumours. Caution is urged, as the original Nature articles studied mice rather than humans, yet Dr Brisken suggested that carefully planned clinical trials could determine the benefits of the drug in affected patients.
Surayya Johar – In-house Editor, Breast Cancer Research