GERD is characterized by the backflow (reflux) of acid or stomach contents from the stomach to the esophagus, where it may damage delicate esophageal tissue. A small percentage of people with GERD go on to develop Barrett's esophagus, where cells lining the esophagus are altered. An even smaller percentage of patients with Barrett's eventually develop esophageal cancer, one of the deadliest forms of cancer.

The study examined cancer cells and biopsies from patients with either acid reflux disease or Barrett's esophagus. Previous research has indicated increased levels of reactive oxygen such as hydrogen peroxide in the cells of Barrett's esophagus and esophageal cancer.

Results of this study also showed higher levels of an enzyme called NOX5-S in the precancerous Barrett's cells. The researchers found that the DNA of this enzyme appeared to be significantly altered when it was exposed to acid, producing the excess hydrogen peroxide found in the precancerous cells. Such an excess creates optimal conditions for cancer cells - mainly increased cell growth and decreased cell death.

The researchers were able to confirm that the ability of esophageal cancer cells to thrive was directly related to the presence of the NOX5 enzyme. By removing the enzyme, the acid-stimulating creation of hydrogen peroxide was lessened.

"The role of acid is controversial. But we show that by exposing cells to acid for short periods of time, that affects a particular enzyme, triggering a chain of events that possibly leads to cancer of the esophagus," Weibiao Cao, study author and Rhode Island Hospital researcher and Brown University assistant professor of medicine and surgery, said in a recent news release.

"Now that we have a better understanding of the signaling pathway, we can possibly identify who is at risk of developing cancer by determining the levels of this enzyme," said Cao. "Now that we know the sequence, we may be able to slow down or even block the progression of cancer by blocking these different steps. This may have therapeutic value if we can block this particular enzyme, NOX5, in Barrett's esophageal cancer cells."

The researchers were able to confirm that the ability of esophageal cancer cells to thrive was directly related to the presence of the NOX5 enzyme. By removing the enzyme, the acid-stimulating creation of hydrogen peroxide was lessened.

The study was conducted by researchers from several institutions, including Brown University, Emory University and the University of Michigan. It was published in a recent issue of the Journal of Biological Chemistry.

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