Healthbeat Report: Bacteria & Breast Cancer

October 22, 2009 For years researchers have been looking at everything from diet to genetics as possible risk factors for breast cancer. But most women still don't know what really caused their disease. That's why attention is now turning to bacteria. Chicago researchers say these microscopic organisms are so powerful they may actually influence who gets breast cancer and who doesn't.

You are what you eat. It's an old saying that's now accepted as truth.

Scientists know that women who eat lots of fatty foods and few fruits and vegetables have a higher risk of breast cancer. Women with a healthy diet seem to have less risk. But what we don't know is why.

Gastroenterologist Ece Mutlu says that's why it's time to focus below the belt. She believes bacteria in the intestines have been overlooked as a major factor in cancer and she's now heading a study to find out more.

"If a person eats fruits and vegetables when they have a lower rate of breast cancer it may be because their bacteria could be metabolizing substances that are linked to breast cancer such as carcinogens and getting rid of them," said Dr. Mutlu, Rush University Medical Center.

Another theory is certain bacteria may help a women better process hormones such as estrogen that have also been linked to breast cancer.

And then there is the flip side.

"It could be that people who get breast cancer have a so called bad set of bacteria that metabolize things differently either increase exposure to carcinogens or substances that cause cancer," said Dr. Mutlu.

The human body has quite the love hate relationship with these tiny organisms. We know some bacteria can be deadly and others balance our gut keeping us healthy. But these billions of microscopic life forms ay be doing even more affecting cells and chemicals in our bodies in ways we don't yet understand.

Newer technologies are providing insight doctors never had in the past.

Breast oncologist Melody Cobleigh says it's an area worth exploring.

"It's a brand new way of looking at the cause of breast cancer…we have no idea why 75 percent women who get breast cancer get it. Hopefully the idea is right the these are the very beginning stages a thesis," said Dr. Meoldy Cobleigh, Rush University Medical Center.

Rush University Medical Center is now collecting and studying bacteria in women who don't have the disease and in those who have been newly diagnosed with breast cancer.

"This may be one of those 'ah ah' moments in science where somebody thinks of something outside the established paradigm and has a brilliant insight," said Dr. Meoldy Cobleigh.

Chicago attorney Mary Fontaine didn't think twice about joining the study. She was diagnosed with breast cancer this year and says she is doing well. Participation involves an intestinal biopsy, blood work and an extensive family history.

"You don't know what causes it or how to negate it's effects how to stop it from coming back so any opportunity to help somebody find that out seems like a great thing to do," said Fontaine.

Current studies show a lot of the bacteria we carry in our bodies was actually passed on to us from our mothers. Researcher say that may also explain why breast cancer runs in some families. The Rush study is being funded by the department of defense and the National Institutes of Health.

For more information on the study, visit or call 312-942-3466.

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