A new study in mice has found that chronic stress may increase susceptibility to a type of skin cancer that is induced by ultraviolet (UV) radiation by suppressing T cells and certain molecules that support immune function.

Both chronic stress and exposure to UV radiation suppress the immune system, but the mechanism by which suppression occurs is not fully understood. A group of scientists at Ohio State University in Columbus, led by Firdaus S. Dhabhar, Ph.D., wanted to find out if and how UV radiation and chronic stress act together to increase susceptibility to disease. They studied immune response and tumor formation in mice exposed to either UV radiation or to UV radiation and chronic stress.

In mice that were exposed to both UV radiation and chronic stress, tumors formed more quickly than in mice that were only exposed to UV radiation. Researchers observed suppression of T-cell function and molecules called type 1 cytokines, both of which work to enhance immune functioning. The authors write, "Our results show that a moderate chronic stressor, one that does not have overall health-aversive effects (no change in body and organ weights), can substantially increase susceptibility to skin cancer."

Contact: Firdaus S. Dhabhar, Ohio State University, 614-209-0602, dhabhar@rockefeller.edu

Dairy Product and Calcium Intake May Be Associated with Increased Risk of Prostate Cancer

Although the most recent U.S. government guidelines recommend that Americans increase their dairy product intake, several studies have reported that high intake of dairy products and calcium is associated with an increased risk of prostate cancer.

In a meta-analysis, Xiang Gao, Ph.D., and Katherine L. Tucker, Ph.D., at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
'"/>

Contact: Ariel Whitworth
jncimedia@oxfordjournals.org
301-841-1287
Journal of the National Cancer Institute
6-Dec-2005