Osteoporosis Drug Could Potentially Prevent Breast Cancer

Researchers recently found the drug denosumab, which typically treats bone disorders such as osteoporosis, may prevent breast cancer in patients with a mutated BRCA1 gene.

"By thoroughly dissecting how normal breast tissue develops, we have been able to pinpoint the precise cells that are the culprits in cancer formation," said researcher Jane Visvader, BSc, PhD. "It is very exciting to think that we may be on the path to the 'holy grail' of cancer research, devising a way to prevent this type of breast cancer in women at high genetic risk."

Since many women whose BRCA1 gene is mutated undergo surgery to prevent breast and ovarian cancer, these findings could prevent unnecessary surgical prevention. Researchers in the study, published by Nature Medicine, included samples of breast tissue from patients with a mutated gene and were able to find the cells responsible for breast cancer.

"These cells proliferated rapidly, and were susceptible to damage to their DNA, both factors that help them transition towards cancer," said researcher Emma Nolan, a PhD student. "We were excited to discover that these pre-cancerous cells could be identified by a marker protein called RANK."

Researchers said that this discovery was an important breakthrough because there are treatments that are able to inhibit the RANK protein.

"An inhibitor called denosumab is already used in the clinic to treat osteoporosis and breast cancer that has spread to the bone," said researcher Geoffrey J Lindeman, BSc, MB BS, PhD. "We therefore investigated what effect RANK inhibition had on the cancer precursor cells in BRCA1-mutant breast tissue."

Researchers showed that RANK-inhibitors were able to switch of cell growth in breast tissue in samples with mutated BRCA1 to reduce cancer development, according to the study.

"We think this strategy could delay or prevent breast cancer in women with an inherited BRCA1 gene mutation. A clinical trial has already begun to investigate this further,” concluded Dr Lindeman. "This is potentially a very important discovery for women who carry a faulty BRCA1 gene, who have few other options. Current cancer prevention strategies for these women include surgical removal of the breasts and/or ovaries, which can have serious impacts on people's lives. To progress this work, denosumab would need to be formally tested in clinical trials in this setting as it is not approved for breast cancer prevention.”