Epigenetics and breast cancer—this is a topic that sounds like science fiction, but it’s not.


If you’re not familiar with epigenetics, it’s the ability of the body to change which genes it expresses and to pass that expression down to its offspring.


That is to say, when you get into epigenetics, for better or for worse, your choices and experiences affect your children and grandchildren.

Two Groups of Pregnant Rats – Two Different Diets

Every pregnant woman faces that possibility that what she eats affects the child growing inside her. However, a new study at Georgetown Lombardi finds that a diet high in fat during pregnancy can increase the risk of breast cancer over several generations. This is likely due to epigenetic modifications.


In the study, pregnant rats were split into two groups. Researchers fed the experimental group a diet high in corn oil, with 40% of calories coming from fat, starting in their second trimester. The remaining rats in the control group received a normal diet, where only 18 percent of their energy came from fat. Both groups of rats ate the same number of calories, and all rats weighed the same.


Genetic Predisposition for Breast Cancer in Offspring

The high fat diet caused genetic changes in the offspring, which predisposed them for breast cancer. That increased risk remained all the way to the great-granddaughters of the original pregnant rats.


Researchers believe the key to passing down the breast cancer risk is that they changed the rats’ diet in the second trimester.  The second trimester is when the rat’s daughters are beginning to form eggs. Epigenetic modifications during this time can alter the genetic information passed to future generations.


Unfortunately, the changes in the rats were not just for a higher breast cancer risk. It also caused an increased resistance to cancer treatments with a poorer prognosis and impaired anti-cancer immunity.

Epigenetics and Breast Cancer Impact

“It is believed that environmental and life-style factors, such as diet, plays a critical role in increasing human breast cancer risk, and so we use animal models to reveal the biological mechanisms responsible for the increase in risk in women and their female progeny,” senior author Leena Hilakivi-Clarke, professor of oncology at Georgetown University, said.


Studies have shown pregnant women eat more fat than non-pregnant women. Most of the increase likewise takes place between the first and second trimesters.


“Of the 1.7 million new cases of breast cancer diagnosed in 2012, 90 per cent have no known causes,” she said. “Putting these facts, and our finding, together really does give food for thought.”

Author Robin Gardner

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