Western Diet May Increase Breast Cancer, Metastases

Elevated fat and cholesterol levels found in Western diets may increase the risk and metastases of breast cancer, according to a new study published in the American Journal of Pathology.

Researchers at the Kimmel Cancer Center at Jefferson examined the role of fat and cholesterol in breast cancer development using a mouse model. The results showed mice fed a Western diet and predisposed to develop mammary tumors, can develop larger tumors that are faster growing and metastasize more easily, compared to animals eating a control diet.

The researchers used the PyMT mouse model to determine the role of dietary fat and cholesterol in tumor development. The model is believed to closely parallel the pathogenesis of human breast cancer. PyMT mice were placed on a diet that contained 21.2 percent fat and 0.2 percent cholesterol, reflective of a typical Western diet. A control group of PyMT mice was fed a normal chow that had only 4.5 percent fat and negligible amounts of cholesterol.

The findings revealed tumors began to develop quickly in mice fed the fat/cholesterol-enriched food. In fact, the number of tumors was almost doubled, and they were 50 percent larger than those observed in mice that ate a normal diet.

"The consumption of a Western diet resulted in accelerated tumor onset and increased tumor incidences, multiplicity, and burden, suggesting an important role for dietary cholesterol in tumor formation," the researchers said, adding there was a trend toward an increased number of lung metastasis in mice fed the fatty diet.

Next, the researchers studied the levels of several biomarkers of tumor progression and found a signature of a more advanced cancer stage, compared to tumors that developed in the control group. Plasma cholesterol levels in experimental mice that developed tumors also were significantly reduced compared to a group of mice with no predisposition to develop tumors that also was fed a cholesterol-rich diet.

"This suggests that tumor formation was responsible for the reduction in blood cholesterol levels observed in our animals," they said.

Sources:

* Kimmel Cancer Center at Jefferson: High Dietary Fat, Cholesterol Linked to Increased Risk of Breast Cancer

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