New genes hold promise of new breast cancer chemoprevention

By Mardi Chapman

25 Oct 2017

An international collaboration co-led by Australian researchers has identified 72 new genetic variants associated with a high risk of breast cancer.

One study identified 65 genetic variants that predispose women to an overall risk of breast cancer while a second study found seven genetic variants that predispose women specifically to oestrogen-receptor negative breast cancer.

Professor Georgia Chenevix-Trench, coordinator of Genetics and Computational Biology at QIMR Berghofer Medical Research Institute, told the limbic the findings held the promise of new risk reduction medications in the future.

“It won’t change clinical practice today – not least because there isn’t a clinically available test – but it’s useful to know when talking to patients, particularly women with a family history who are concerned about their risk and that of their children.”

She said it was encouraging that this kind of basic research would very likely turn into better ways of preventing, not just treating breast cancer.

“And hopefully in a much shorter time these tests will be integrated into the general population so instead of starting mammograms at 50 years of age, women might have genetic tests at 35 to 40 years to categorise them as either low, medium or high risk.”

“Those with a high risk might have accelerated screening and those at reduced risk might defer screening or have it less regularly,” she said.

Professor Chenevix-Trench said once the best possible combination of genetic variants to predict breast cancer risk was determined, the findings could start to be applied in women who carry BRCA1 or BRCA2 mutations.

“Even though there is a fairly small overall risk conferred by these variants, when you already have a high risk, the change in absolute risk is quite extreme.”

“These are also the women who are making decisions on a daily basis about when they should start screening, when should they consider prophylactic mastectomy or oophorectomy, and whether they should take tamoxifen to reduce their risk.”

The study found there was overlap between inherited gene mutations driving risk of breast cancer and those acquired during the development of the tumours.

“And that suggests that once we develop new drugs they could potentially be used for both prevention and treatment, just as tamoxifen is now.”

“Ideally the long term aim of our research is to find new risk reduction medications that could be as powerful and as effective as statins are in reducing deaths from heart disease,” she said.


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