It is not the cholesterol itself, but a “byproduct of cholesterol (that) functions like the hormone estrogen to fuel the growth and spread of the most common types of breast cancer,” researchers at the Duke University Cancer Institute report, according to Newswise.
Estrogen is known to “feed an estimated 75 percent of all breast cancers,” Newswise reports. So basically, cholesterol creates a “byproduct” that acts like estrogen and “feeds” the breast cancer, the researches concluded.
This is the first time a link between high cholesterol and breast cancer has been explained, especially in post-menopausal women, according to the study, which also suggests that changes in diet or taking statins and other medication to reduce cholesterol may offer “simple ways to reduce breast cancer risk,” Newswise reports.
Although studies have shown a connection between obesity and breast cancer, as well as high cholesterol and breast cancer, the reason for these connections had not been explained, said senior author Donald McDonnell, chairman of the Department of Pharmacology and Cancer Biology at Duke: “What we have now found is 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.”
The researchers also found that the more enzyme that makes the cholesterol byproduct that is present, the more aggressive the tumor.
When test animals took anti-estrogen drugs such as tamoxifen, or when they quit receiving the cholesterol byproduct, the cancer was inhibited, according to Newswise.
Nelson said in the article that there was also a potential association between the cholesterol byproduct and the development of resistance to the anti-estrogen tamoxifen. Data also suggest the cholesterol byproduct may reduce the effectiveness of commonly used breast cancer therapies.
These findings suggest that women who have breast cancer and high cholesterol who take statins will have increased benefit, Newswise reports, because it will decrease their resistance to commonly used breast cancer therapies.
Further research will “include clinical studies to verify the suggested potential outcomes and to determine if this cholesterol byproduct plays a role in other cancers,” McDonnel said.
Kentucky Health News is an independent news service of the Institute for Rural Journalism and Community Issues, based in the School of Journalism and Telecommunications at the University of Kentucky, with support from the Foundation for a Healthy Kentucky.