Why high cholesterol fuels growth and spread of breast cancer

Washington – Researchers have suggested that breast cancer growth can be fuelled by high cholesterol, as a by-product of cholesterol functions like the hormone estrogen to enhance the growth and spread of the disease.

The researchers at the Duke Cancer Institute also found that anti-cholesterol drugs such as statins appear to diminish the effect of this estrogen-like molecule.

By using mouse models and tumour cells, the researchers have for the first time explained the link between high cholesterol and breast cancer, especially in post-menopausal women, and the study suggested that dietary changes or therapies to reduce cholesterol may also offer a simple, accessible way to reduce breast cancer risk.

Senior author Donald McDonnell, Ph.D., chair of the Department of Pharmacology and Cancer Biology at Duke, said they have found a molecule- not cholesterol itself, but an abundant metabolite of cholesterol- called 27HC that mimics the hormone estrogen and can independently drive the growth of breast cancer.

Using mouse models that are highly predictive of what occurs in humans, McDonnell and colleagues demonstrated the direct involvement of 27HC in breast tumour growth, as well as the aggressiveness of the cancer to spread to other organs.

They also noted that the activity of this cholesterol metabolite was inhibited when the animals were treated with antiestrogens or when supplementation of 27HC was stopped.

McDonnell said the findings suggested there may be a simple way to reduce the risk of breast cancer by keeping cholesterol in check, either with statins or a healthy diet.

Additionally, for women who have breast cancer and high cholesterol, taking statins may delay or prevent resistance to endocrine therapies such as tamoxifen or aromatase inhibitors.

The study is published in the journal Science.