Environmental and Life-Style Factors Up Breast Cancer Risk

Breast cancer affects one in eight women during their lives. No one knows why some women get breast cancer, but there are many risk factors. Avoid a high-fat diet if you are pregnant as research has found that it increases the breast cancer risk. Feeding pregnant female mice a diet high in fat derived from common corn oil resulted in genetic changes that substantially increased breast cancer susceptibility in three generations of female offspring, reported a team of researchers led by scientists at Georgetown Lombardi Comprehensive Cancer Center. The study suggested a research direction for examining the diet of pregnant women, said senior author Leena Hilakivi-Clarke.

"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," said Hilakivi-Clarke. A high-fat diet is linked to excess inflammation and a number of epidemiological studies have made the connection between inflammation and risk of cancer, she noted. This study found that if pregnant mice were switched to a high fat diet during their second trimester when the germ line mediating genetic information from one generation to another forms in the foetus, an increase in breast cancer risk is also seen in "great granddaughters."

A gene screen revealed a number of genetic changes in the first (daughter) and third (great granddaughter) high-fat mice generations, including several genes linked in women to increased breast cancer risk, increased resistance to cancer treatment, poor cancer prognosis and impaired anti-cancer immunity. The researchers also found three times as many genetic changes in third generation than first generation mammary tissue between high-fat diet progeny and the control group's offspring.

"The soil in the breast, so to speak, remained fertile for breast cancer development in our high-fat experimental mice," Hilakivi-Clarke continued. The amount of fat fed to the experimental mice matched what a human might eat daily, said Hilakivi-Clarke. In the study, both the control mice and the mice fed chow with high levels of corn oil ate the same amount of calories and they weighed the same. "But our experimental mice got 40 percent of their energy from fat, and the control mice got a normal diet that provided 18 percent of their energy from fat," she said. "The typical human diet now consists of 33 percent fat." The study is published online in Breast Cancer Research.

Source-ANI