Breast cancer

Updated 08 November 2017

The DNA of breast cancer

Globally, breast cancer is the most frequently diagnosed cancer amongst women. Could you have a genetic predisposition to develop breast cancer?

Globally, breast cancer is the most frequently diagnosed cancer amongst women in both the developed and developing world. In 2010 alone, more than 1.5 million women were diagnosed with breast cancer with an estimated 10.9% of the world’s total female population affected. Locally, one in 29 South African women are impacted with an estimated 3 000 dying from the disease each year.

Numerous studies have linked prolonged exposure to both endogenous (occurs naturally within the body) and exogenous (externally administered) oestrogen to breast cancer. In fact, research has consistently found that women who use Hormone Replacement Therapies (HRTs), typically prescribed to offset menopause symptoms, for five years or more increase their risk of breast cancer by approximately 35%.

Dr Gys du Plessis, advisor for DNAlysis Biotechnology, practising in integrative and functional medicine and medical director for Nimue Bioscience, explains that sex steroids, such as oestrogen, have a variable metabolism that is strongly influenced by your DNA and other environmental factors.

Genetic  predisposition

"The 0.1% difference in every individual’s genes creates a variance in biological processes, including oestrogen metabolism. The result is a genetic predisposition to certain diseases such as breast cancer, diabetes, cardiovascular disease and high cholesterol to name a few examples. Women who are genetically unable to efficiently metabolise and eliminate excess oestrogen face a significantly higher risk of developing breast cancer, particularly when taking additional hormones such as oral contraceptives or HRTs."

Thankfully, recent advancements in the Human Genome Project have led to the development of targeted DNA testing which provides invaluable insights into our genetic strengths and weaknesses.

Earlier this year, DNAlysis Biotechnology launched South Africa’s first oestrogen metabolism genetic test, which identifies eight genes and 12 gene variations associated with oestrogen metabolism and detoxification in women.

DNA testing

"The test provides medical practitioners with a scientific tool to asses a patient’s breast cancer risk and manage it accordingly. The information, coupled with other considerations unique to the individual means that doctors are far better informed prior to prescribing HRTs. Similarly, women making these lifestyle decisions are now also better informed of their risk," says du Plessis.

The test is only available via healthcare practitioners who have completed the necessary training to interpret the findings and offer an informed diagnosis. A training programme is available via DNAlysis Biotechnology and has been so successful that South Africa now has what is probably one of the largest networks of healthcare practitioners in the world that are qualified to interpret DNA tests and provide suitable diet, exercise and healthcare regimes to clients.

“Genetics is playing an increasingly important role in the diagnosis and holistic treatment of disease, and will change how we support health, diagnose and treat human disease and develop interventions. We hope that, within the next five years, the oestrogen metabolism test will be available to all women in South Africa,” du Plessis concludes.

For more information on DNAlysis Biotechnology visit

 DNALYSIS Biotechnology press release

- (Health24, October 2012)


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Breast cancer expert

Dr Gudgeon qualified in Birmingham, England, in 1968. She has more than 40 years experience in oncology, and in 1994 she founded her practice, Cape Breast Care, where she treats benign and malignant breast cancers. Dr Boeddinghaus obtained her qualification at UCT Medical School in 1994 and her MRCP in London in 1998. She has worked extensively in the field of oncology and has a special interest in the hormonal management of breast cancer. She now works with Dr Gudgeon at Cape Breast Care. Read more.

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