PHILADELPHIA, Dec. 28 (UPI) -- A U.S. researcher studying a cancer-targeting molecule called TRAIL unexpectedly found a connection between inflammation and cancer susceptibility.

Dr. Wafik S. El-Deiry of the University of Pennsylvania School of Medicine has been studying the cancer-targeting molecule TRAIL for more than 10 years. The molecule is normally produced by immune cells and curtails tumor spread by binding to a specialized receptor on a tumor's surface.

When intact, TRAIL and its receptor decrease the influx of inflammatory cells and molecules that can lead to cancer.

Test mice without the TRAIL receptor that were irradiated developed chronic pneumonia, an inflammatory response, as well tumors -- evidence pointing to the connection between cancer and inflammation via TRAIL.

"One benefit of this work is that it provides a new and unanticipated model implicating a TRAIL pathway deficiency in the chronic toxicity of radiation therapy," El-Deiry said in a statement. "Inflammation is a common late and serious side-effect of radiation treatment in people."

The findings are published online in the Journal of Clinical Investigation in advance of the January print issue.