(Press-News.org) (PHILADELPHIA) Elevated fat and cholesterol levels found in a typical American-style diet play an important role in the growth and spread of breast cancer, say researchers at the Kimmel Cancer Center at Jefferson.
The study, published in the January issue of The American Journal of Pathology, examines the role of fat and cholesterol in breast cancer development using a mouse model. The results show that 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 research team led by cancer biologist Philippe G. Frank, Ph.D., Assistant Professor in the Department of Stem Cell Biology and Regenerative Medicine at Thomas Jefferson University, was interested in learning about the link between diet and breast cancer. The incidence rate of this cancer is five times higher in Western countries than in other developed countries. Moreover, studies have shown an increase in breast cancer incidence in immigrant populations that relocate from a region with low incidence. "These facts suggest strong environmental influence on breast cancer development," says Dr. Frank.
Dietary fat and cholesterol have been shown to be important risk factors in the development and progression of a number of tumor types, but diet-based studies in humans have reached contradictory conclusions. This has led Dr. Frank to turn to animal models of human cancer to examine links between cholesterol, diet, and cancer.
The research team turned to the PyMT mouse model to determine the role of dietary fat and cholesterol in tumor development. This mouse 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 researchers found that tumors began to develop quickly in mice fed the fat/cholesterol-enriched chow. In this group, 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," Dr. Frank says. There was also a trend towards an increased number of lung metastasis in mice fed the fatty diet, he adds.
To confirm the aggressive nature of the cancer in animals fed a cholesterol-rich diet, the researchers examined 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.
The researchers also showed that plasma cholesterol levels in experimental mice that developed tumors were significantly reduced compared to a group of "wild-type" mice – animals with no predisposition to develop tumors – that was also fed a cholesterol-rich diet. "This suggests that tumor formation was responsible for the reduction in blood cholesterol levels observed in our animals," indicates Dr. Frank.
Dr. Frank explains the use of cholesterol in breast tumors this way: "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," indicates Dr. Frank. These findings suggest that use of cholesterol-lowering drugs, such as statins, may both protect against breast cancer as well as treat patients carrying tumors. Since researchers also found that blood cholesterol levels dropped significantly as tumors began to develop, the study indicates measuring blood cholesterol levels may also be an effective method of screening cancer development.
This research team also discovered the same association between cholesterol and growth of prostate cancer in mice in a study published in the December issue of The American Journal of Pathology. The results of these two new studies indicate, according to Dr. Frank that, "Cholesterol does indeed seem to be an important factor in the regulation of tumor formation in several cancer types."
INFORMATION: END
Madison, WI December 28, 2010 – The Australian Government National Water Commission funded a study to establish an approach to assess the quality of water treated using managed aquifer recharge. Researchers at Australia's CSIRO Land and Water set out to determine if the en product would meet standard drinking water guidelines.
At the Parafield Aquifer Storage, Transfer and Recovery research project in South Australia, the team of scientists harvested storm water from an urban environment, treated it in a constructed wetland, stored it in an aquifer, and then recovered ...
Menlo Park, Calif. — The Crab Nebula, one of our best-known and most stable neighbors in the winter sky, is shocking scientists with a propensity for fireworks—gamma-ray flares set off by the most energetic particles ever traced to a specific astronomical object. The discovery, reported today by scientists working with two orbiting telescopes, is leading researchers to rethink their ideas of how cosmic particles are accelerated.
"We were dumbfounded," said Roger Blandford, who directs the Kavli Institute for Particle Astrophysics and Cosmology, jointly located at ...
An international, NOAA-led research team took a significant step forward in understanding the atmosphere's ability to cleanse itself of air pollutants and some other gases, except carbon dioxide. The issue has been controversial for many years, with some studies suggesting the self-cleaning power of the atmosphere is fragile and sensitive to environmental changes, while others suggest greater stability. And what researchers are finding is that the atmosphere's self-cleaning capacity is rather stable.
New analysis published online today in the journal Science shows that ...
(Santa Barbara, Calif.) –– Calling the results "extremely surprising," researchers from the University of California, Santa Barbara and Texas A&M University report that methane gas concentrations in the Gulf of Mexico have returned to near normal levels only months after a massive release occurred following the Deepwater Horizon oil rig explosion.
Findings from the research study, led by oceanographers John Kessler of Texas A&M and David Valentine of UCSB, were published today in Science Xpress, in advance of their publication in the journal Science. The findings show ...
AMES, Iowa – An international team of scientists has released data indicating that greenhouse gas uptake by continents is less than previously thought because of methane emissions from freshwater areas.
John Downing, an Iowa State University professor in the ecology, evolution and organismal biology department, is part of an international team that concluded that methane release from inland waters is higher than previous estimates.
The study, published in the journal Science, indicates that methane gas release from freshwater areas changes the net absorption of greenhouse ...
CHICAGO (January 6, 2011) – According to a report published in the December issue of the Journal of the American College of Surgeons, surgery residents improved their knowledge of health care business concepts and principles with the use of a Web-based curriculum.
The expectation is for residents to "demonstrate an awareness of and responsiveness to the larger context and system of health care, as well as the ability to call effectively on other resources in the system to provide optimal health care." However, consensus from residents is that they lack instruction and ...
Queen's University Classics professor emeritus Ross Kilpatrick believes the Leonardo da Vinci masterpiece, the Mona Lisa, incorporates images inspired by the Roman poet Horace and Florentine poet Petrarch.
The technique of taking a passage from literature and incorporating it into a work of art is known as 'invention' and was used by many Renaissance artists.
"The composition of the Mona Lisa is striking. Why does Leonardo have an attractive woman sitting on a balcony, while in the background there is an entirely different world that is vast and barren?" says Dr. Kilpatrick. ...
GAINESVILLE, Fla. — A new University of Florida study following the evolution of lice shows modern humans started wearing clothes about 170,000 years ago, a technology which enabled them to successfully migrate out of Africa.
Principal investigator David Reed, associate curator of mammals at the Florida Museum of Natural History on the UF campus, studies lice in modern humans to better understand human evolution and migration patterns. His latest five-year study used DNA sequencing to calculate when clothing lice first began to diverge genetically from human head lice. ...
LOS ANGELES, Calif. — January 6, 2011 — Pharmaceutical companies and generic drug manufacturers have long been at odds over regulations about "data exclusivity," the period of time before generic manufacturers can make use of valuable clinical trial data.
A new study in the January 2011 issue of Health Affairs is the first to calculate the financial and social costs of limiting access to trial data — and finds that extending the term of exclusive access will lead to higher drug costs in the short term but also to more than 200 extra drug approvals and to greater life ...
One of the most enduring mysteries in solar physics is why the Sun's outer atmosphere, or corona, is millions of degrees hotter than its surface.
Now scientists believe they have discovered a major source of hot gas that replenishes the corona: jets of plasma shooting up from just above the Sun's surface.
The finding addresses a fundamental question in astrophysics: how energy is moved from the Sun's interior to create its hot outer atmosphere.
"It's always been quite a puzzle to figure out why the Sun's atmosphere is hotter than its surface," says Scott McIntosh, ...
