In a breakthrough, scientists have found that a drug used to treat bone loss may potentially prevent or delay breast cancer in women at high risk of developing the disease.
Researchers discovered that the existing medication could have promise in preventing breast cancer in women carrying a faulty BRCA1 gene.
People who carry a faulty BRCA1 gene are at high risk of developing aggressive breast cancer. Currently many women with a gene mutation choose surgical removal of their breast tissue and ovaries to reduce their chance of developing breast and ovarian cancer.
By pinpointing the cells that give rise to breast cancers in women who have inherited a faulty version of the BRCA1 gene, researchers at the Walter and Eliza Hall Institute in Australia identified that the drug denosumab may have potential to prevent breast cancer from developing.
If confirmed in clinical studies, this would provide a non-surgical option to prevent breast cancer in women with elevated genetic risk, researchers said.
Using samples of breast tissue donated by women carrying a faulty BRCA1 gene, researchers were able to pinpoint the cells that give rise to breast cancer.
Cancer precursor cells in BRCA1-mutant breast tissue had many similarities to aggressive forms of breast cancer, said Emma Nolan, a PhD student at the institute.
"These cells proliferated rapidly, and were susceptible to damage to their DNA - both factors that help them transition towards cancer," she said.
"We were excited to discover that these pre-cancerous cells could be identified by a marker protein called RANK," said Nolan.
Geoff Lindeman, a medical oncologist at The Royal Melbourne Hospital, said the discovery of RANK as a marker of cancer precursors was an important breakthrough, because inhibitors of the RANK signalling pathway were already in clinical use.
"An inhibitor called denosumab is already used in the clinic to treat osteoporosis and breast cancer that has spread to the bone," he said.
"We therefore investigated what effect RANK inhibition had on the cancer precursor cells in BRCA1-mutant breast tissue," said Lindeman.
The research team showed that RANK inhibition switched off cell growth in breast tissue from women with a faulty BRCA1 gene and curtailed breast cancer development in laboratory models.
"We think this strategy could delay or prevent breast cancer in women with an inherited BRCA1 gene mutation," Lindeman said.
"A clinical trial has already begun to investigate this further," said Lindeman.
The research was published in the journal Nature Medicine.
