Scientists have worked out how the breast cancer gene BRCA1 causes breast cancer, an advance that could lead to new forms of cancer treatment in the future.
Although the gene was discovered more than ten years ago, researchers have only now discovered how mutations in the gene cause breast cancer.
Now, an international team from Columbia University and Lund University in Sweden have found that it knocks out a tumour suppressor gene called PTEN, causing a pro-growth signal to be sent to tumour cells.
According to researcher Ramon Parsons, a professor at Columbia University College of Physicians and Surgeons, the findings are "exciting".
Professor Parsons said: "We have been stymied by our limited resources to treat these cancers, which are associated with very poor prognoses.
"Now that we know that PTEN is involved, we finally have a target for therapy for these cancers."
BRCA1 also increases the risk of ovarian, bowel and prostate cancer.