Why some ulcers may go on to cancer

NASHVILLE, Aug. 26 (UPI) -- U.S. researchers say they are finding clues as to how certain proteins may link some bacteria in the digestive system with cancer.

The study, published in the Journal of Biological Chemistry online, focuses on a group of bacteria that can infect the digestive system known as Helicobacter pylori or H. Pylori. In a few number of cases, H. Pylori bacterial infection leads to cancer.

The researchers found one strain of H. pylori bacteria -- the H. pylori cag-plus strain -- contains a set of proteins that could be key to chronic damage.

Study corresponding author Richard Peek of the Vanderbilt University School of Medicine in Nashville says that the protein -- CagE -- can induce gastric cells to turn on a receptor called decay-accelerating factor, which acts to remove nearby immune proteins that normally would kill cells and prevent unwanted immune damage.

In essence, says Peek, the bacteria use the decay-accelerating factor receptor on the host cell they're attached to like a bodyguard to protect them from the immune system. He notes that by continually inducing decay-accelerating factor expression, H. pylori creates an environment of persistent inflammation that can reduce the threshold required for more serious diseases to develop.