October 9, 2008

Bacterial Link to Colon Cancer Studied

U.S. researchers say they have discovered the human colon reacts to changes in a common bacterium in ways that might promote the growth of cancer.

Researchers from the Department of Veterans Affairs Medical Center in Oklahoma City and from the University of Oklahoma studied a bacterium called Enterococcus faecalis that's commonly found in the human colon. The scientists said that bacterium can release a type of oxygen molecule called a superoxide, that damages DNA and might promote the growth of cancer cells in the colon.

"We wanted to investigate how colon cells respond to normal gut bacteria that can damage DNA, like E. faecalis," said Professor Mark Huycke of the VA Medical Center. He added that the researchers "found superoxide from E. faecalis led to strong signaling in immune cells called macrophages. It also altered the way some cells in the gut grew and divided and even increased the productivity of genes that are associated with cancer."

Huycke said the findings are among the first to explore mechanisms by which normal gut bacteria damage DNA and alter gene regulation in the colon that might lead to cancer.

The study appears in the Journal of Medical Microbiology.