What is science saying about breast cancer? Sunscreen and high-fat diets.

Notre Dame Researchers Studying Breast Cancer

It’s October, which means it’s breast cancer awareness month. We are going to do something a little unique to mark the occasion. For the month we will be exploring what science is saying about breast cancer, risks, and potential cures.

We’ll start with a recent question being asked by Michigan State University scientists: is there a link between a high-fat diet and the usage of sunscreen containing the chemical Benzophenone-3 with an increased risk of breast cancer?

Of course, a little background might be helpful to knowing why they asked that question. Benzophenone-3, or BP-3 for short, filters UV rays. It is the screen in your sunscreen. Benzophenones in general are lipophilic, which means they tend to combine with or dissolve in lipids or fats. They are absorbed by the skin and that’s how they enter the human body.

Previous studies have shown that BPs are able to mimic estrogen in the environment, which can in turn lead to an increased proliferation of estrogen receptor (ER)-positive breast cancer cells. A 2013 study concluded that “direct application of BP-based sunscreen on the breast and the subsequent skin absorption could favor the proliferation of ERα-positive epithelial cells, increasing the probability of developing a breast cancer or stimulating the growth and progression of a pre-existing tumor.”

So putting it all together we come up with the question we asked above. Knowing that BP-3 easily dissolves and accumulates in fats and that it can function like estrogen in the body, is there a link between a high-fat diet, the usage of BP-based sunscreen, and an increase in the risk of breast cancer?

One of the researchers, professor of Microbiology and Molecular Genetics Richard Schwartz, believes that their research could have a profound affect on “many women as diets high in fat are widespread and sunscreens with certain chemicals are routinely promoted as protection against skin cancer.”

The $4.1 million grant was awarded by the National Institute of Environmental Health Sciences. Schwartz, along with Sandra Haslam, a professor of physiology in the College of Human Medicine, will lead the study.

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