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Researchers make major genetic discovery regarding breast cancer risk

[Dec 24, 2022: Lea Jones, University of Otago]

A global study led by the University of Otago has discovered a gene, that when modified, could reduce the risk of breast cancer. (CREDIT: Getty Images)

A global study led by the University of Otago has discovered a gene, that when modified, could reduce the risk of breast cancer.

The discovery, led by Associate Professor Logan Walker, of the Department of Pathology and Biomedical Science, Christchurch, also opens the door to the development of a risk-reducing drug – a project which has already received funding and will also be led by Otago University.


The initial study was the world’s largest of women known to have mutations of the breast cancer genes – BRCA1 and BRCA2.

It made two “significant” discoveries.

“We have found a gene – the SULT1A1 - that may help doctors decrease the chance of woman getting breast cancer, especially if they have also inherited a mutation in the BRCA1 gene,” Associate Professor Walker says.


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“We have also found that women who have inherited a BRCA1 gene with segments missing are, for reasons as yet unknown, at the highest risk of developing breast cancer.”

The study, in collaboration with the international Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), involved about 26,000 women known to have mutations in the BRCA1 or BRCA2 genes, and 166 researchers from 160 institutes world-wide.


Associate Professor Logan Walker.

In New Zealand, about one in every 250 individuals inherit a genetic mutation in these two genes, which means they are at high-risk of developing breast and ovarian cancer. However, the risk of cancer for these individuals varies significantly due to other unknown genetic changes, creating a significant challenge for counselling and clinical decision making.

Currently, the most effective risk-reducing strategy for these women at high risk of breast cancer is a bilateral mastectomy. Although effective, this approach is irreversible and can cause ongoing psychological and physiological harm to patients, especially for younger women, Associate Professor Walker says.

The study found that reduced levels of the protein produced by the SULT1A1 gene, that plays an important role in the metabolism of cancer-causing agents, lowered the risk of breast cancer.


“When we turned down the activity of the SULT1A1 gene in breast cells, the cells grew more slowly and were more resistant to DNA damage. This anti-cancer-like feature supported epidemiological results from 26,000 women,” he says.

The next step is developing a risk reducing drug – a project which will be led by Otago’s Dr George Wiggins.

“Prophylactic drug treatments are becoming well-established for the prevention of different diseases. For example, aspirin, statins and anti-hypertensive therapies have had a major impact on reducing incidence of cardiovascular disease and extending life expectancy,” he says

“By comparison, progress in therapeutic intervention to prevent breast cancer has been poor. Providing a non-invasive and easily accessible preventative therapy for women at high risk of developing breast cancer would have numerous benefits for the health system, and for the patients and their whānau.

“Such a therapy could give genetically predisposed young women the opportunity to bear and breastfeed their children by delaying or supplanting the need for risk-reducing surgery.”


In New Zealand, breast cancer is the most commonly diagnosed cancer in Māori and non-Māori women, with more than 3,300 individuals diagnosed and more than 600 deaths per year.

“Uptake of risk reducing surgery can also be a barrier to breast cancer prevention for many individuals, contributing to inequity in health outcomes,” Associate Professor Walker says.

Characterisation of MCF7–WT, and isogenic MCF7–C1, and MCF7–BRCA1+/− cell lines. (CREDIT: Nature Communications)

“Effective prevention strategies for women at increased risk of breast cancer are vital for controlling and reducing the social and economic impact of this disease.


The study was funded through a grant from the Health Research Council of New Zealand.

What Are the Symptoms of Breast Cancer?

According to the CDC, different people have different symptoms of breast cancer. Some people do not have any signs or symptoms at all.

Some warning signs of breast cancer are—

  • New lump in the breast or underarm (armpit).

  • Thickening or swelling of part of the breast.

  • Irritation or dimpling of breast skin.

  • Redness or flaky skin in the nipple area or the breast.

  • Pulling in of the nipple or pain in the nipple area.

  • Nipple discharge other than breast milk, including blood.

  • Any change in the size or the shape of the breast.

  • Pain in any area of the breast.

  • Keep in mind that these symptoms can happen with other conditions that are not cancer.


If you have any signs or symptoms that worry you, be sure to see your doctor right away.

For more science and technology stories check out our New Discoveries section at The Brighter Side of News.


Note: Materials provided above by the University of Otago. Content may be edited for style and length.


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