Existing drug could prevent BRCA1-positive breast cancer

The options for women with BRCA1 mutations are limited: Many elect to have prophylactic surgery to remove breast tissue. Australian researchers have discovered that an existing drug has the potential to ward off breast and ovarian cancers in women who carry a faulty BRCA1 gene.

A team from the Walter and Eliza Hall Institute of Medical Research studied breast tissue donated from women carrying a BRCA1 mutation and found that cancer precursor cells behaved much like the cells in aggressive 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 Ph.D. candidate, in a statement. “We were excited to discover that these pre-cancerous cells could be identified by a marker protein called RANK.”

The team decided to treat their donated breast tissue cells with denosumab, a RANK inhibitor. Denosumab is approved in the U.S. to treat cell tumors of the bone, bone metastasis of solid tumors, including breast tumors, and osteoporosis in postmenopausal women. It is marketed by Amgen ($AMGN) as Prolia and Xgeva.

In laboratory models, denosumab “switched off” cell growth in BRCA1-mutant breast tissue and curbed breast cancer development, the researchers said in the statement. The findings echo an earlier study by an Austrian team that also investigated RANK: “They deleted the RANK gene during development. We switched off the RANK pathway using an inhibitor to recapitulate a breast cancer prevention study in humans. Both studies suggest that targeting RANK offers hope to women at high genetic risk for breast cancer,” said Dr. Geoff Lindeman, a joint division head of the Australian Cancer Research Foundation Stem Cells and Cancer division at Walter and Eliza Hall, in the statement.

“We think this strategy could delay or prevent breast cancer in women with an inherited BRCA1 gene mutation,” Professor Lindeman said. “A clinical trial has already begun to investigate this further.” The drug is not approved for breast cancer prevention.

- here's the statement

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