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Troy, N.Y. -  4/19/2006

New Research May Decode Data from Rodent Cancer Studies for Use in Human Comparisons

Scientists quantify light as a circadian stimulus in breast cancer research

A new paper written by scientists at Rensselaer Polytechnic Institute’s Lighting Research Center (LRC) may help cancer researchers decode results in laboratory studies of light and cancer risk that use mice and rats. “Of mice and women: Light as a circadian stimulus in breast cancer research” will allow researchers to quantitatively compare light levels used in rodent studies with lighting conditions experienced by humans.

Lead author John Bullough, Ph.D., says this is important, because the circadian systems of nocturnal rodents are 1000-10,000 times more sensitive to light than the circadian system of humans.

“Normal room or laboratory lighting,” says Dr. Bullough, “might be a ‘dim circadian stimulus’ to a human, but would be a ‘bright circadian stimulus’ to a mouse or rat.”

The circadian system regulates biological rhythms, including the sleep/wake cycle, hormone production, and body temperature.

Drs. Mark Rea and Mariana Figueiro are co-authors of the paper.

In simple terms, the paper can serve as a "decoder ring" to help in translating lighting conditions experienced by humans in real life to those used in rodent studies. This is especially important as recent studies are beginning to show potential links between lighting (as a circadian stimulus) and cancer risk or tumor growth.

Bullough further explained that humans and nocturnal rodents also have different spectral sensitivity to light. For example, the visual and circadian systems of rats and mice are sensitive to ultraviolet radiation, whereas those of humans are not. Also the human circadian system can decode color information, while that of the mouse cannot.

The paper appears in the May 2006 issue of the journal Cancer Causes and Control (

About the Lighting Research Center
The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute is the world's leading center for lighting research and education. Established in 1988 by the New York State Energy Research and Development Authority (NYSERDA), the LRC conducts research in light and human health, transportation lighting and safety, solid-state lighting, energy efficiency, and plant health. LRC lighting scientists with multidisciplinary expertise in research, technology, design, and human factors, collaborate with a global network of leading manufacturers and government agencies, developing innovative lighting solutions for projects that range from the Boeing 787 Dreamliner to U.S. Navy submarines to hospital neonatal intensive-care units. In 1990, the LRC became the first university research center to offer graduate degrees in lighting and today, offers a M.S. in lighting and a Ph.D. to educate future leaders in lighting. Learn more at

About Rensselaer Polytechnic Institute
Founded in 1824, Rensselaer Polytechnic Institute is America's first technological research university. Rensselaer encompasses five schools, 32 research centers, more than 145 academic programs, and a dynamic community made up of more than 7,900 students and more than 100,000 living alumni. Rensselaer faculty and alumni include more than 145 National Academy members, six members of the National Inventors Hall of Fame, six National Medal of Technology winners, five National Medal of Science winners, and a Nobel Prize winner in Physics. With nearly 200 years of experience advancing scientific and technological knowledge, Rensselaer remains focused on addressing global challenges with a spirit of ingenuity and collaboration.