Jefferson University Hospitals A typical American-style diet containing increased fat and cholesterol levels appears extremely harmful for health. Investigators from the Kimmel Cancer Center at Jefferson claim that raised fat and cholesterol levels are strongly involved in the growth and spread of breast cancer. It was suggested that environmental factors have a strong impact on breast cancer development.

With the help of a mouse model, scientists shed light on the probable role of fat and cholesterol in breast cancer development. It was pointed out that mice fed a Western diet and predisposed to develop mammary tumors develop larger tumors that grow faster and metastasize more easily, as compared to animals subjected to a control diet. Previous investigations have asserted that dietary fat and cholesterol are crucial factors in the development and progression of several tumor types. Having employed a PyMT mouse model, the seeming role of dietary fat and cholesterol in tumor development was highlighted.

“In a neighborhood, if you want to build more houses, you need more bricks. In tumors, cholesterol provides the bricks that are the foundation for further growth, and this cholesterol comes from the blood. A drop in blood cholesterol may signify that some tumors are growing as cholesterol provides support for breast cancer growth. These data provide new evidence for an increase in cholesterol utilization by breast tumors and thus provides many new avenues for prevention, screening, and treatment,” alleged, Cancer biologist Philippe G. Frank, Ph.D., Assistant Professor in the Department of Stem Cell Biology and Regenerative Medicine at Thomas Jefferson University, lead investigator.

PyMT mice ate a diet containing 21.2 percent fat and 0.2 percent cholesterol, reflective of a typical Western diet. The control group of PyMT mice, on the other hand was fed a normal chow that had only 4.5 percent fat and negligible amounts of cholesterol. Mice consuming the fat/cholesterol-enriched chow probably had tumors that developed quickly. The tumors almost doubled and appeared 50 percent larger than those witnessed in mice eating a normal diet. Consumption of a Western diet reportedly elevates tumor onset, incidences, multiplicity, and burden. Experts also noted an increased number of lung metastasis in mice fed the fatty diet.

In order to affirm the aggressive nature of cancer in animals fed a cholesterol-rich diet, the research also evaluated levels of several biomarkers in tumor progression. A signature of a more advanced cancer stage than to tumors developed in the control group was registered. It was demonstrated that plasma cholesterol levels in experimental mice with tumors were drastically declined in comparison to a group of ‘wild-type’ mice that were fed a cholesterol-rich diet. It was concluded that tumor formation is responsible for reducing blood cholesterol levels in animals. Usage of cholesterol-lowering drugs like statins appears beneficial in fighting breast cancer and patients with tumors.

The research is published in the January issue of The American Journal of Pathology.