Thaindian News

Washington, Oct 13 (IANS) Some bacteria like Helicobacter pylori that inhabit the human gut, may help protect against the development of a type of stomach cancer.A review found that people who had H. pylori strains carrying a gene called CagA were almost half as likely to get adenocarcinoma of the esophagus, a cancer that develops in the tube that passes food from the throat to the stomach.

“CagA-positive strains of H. pylori may decrease the risk of adenocarcinoma by reducing acid production in the stomach and, therefore, reducing acid reflux to the esophagus,” said study co-author Farin Kamangar, a research fellow at the National Cancer Institute, at Bethesda in Maryland.

“It may also work by decreasing the production of the hormone ghrelin, which is secreted from the stomach to stimulate appetite. A reduction in the level of ghrelin may lead to lower rates of obesity, an important risk factor for adenocarcinoma,” he added.

H. pylori, estimated to be present in about half the world’s population, is a known cause of stomach cancer and ulcers. Advancements in sanitation and antibiotics have made H. pylori less common and have consequently lowered the incidence stomach cancer and ulcers, according to an Eurekalert report.

However, as H. pylori, including CagA-positive H. pylori, has become less common, esophageal adenocarcinomas have increased. The study suggests that the declining rates of H. pylori in developed populations may be partly responsible for this increase.

Once a rare cancer, esophageal adenocarcinomas as of now constitute approximately half of all esophageal cancers cases in western countries like the US and UK.

Although H. pylori was first discovered in the early 1980s, Kamangar said humans already had been living with the bacteria for 60,000 years. The bacteria were once present in the stomachs of just about everyone.

Despite its potential for causing stomach cancer and ulcers, H. pylori’s long history of co-existence with humans suggests it also may have some beneficial effects, including possible roles in reducing diarrhoeal diseases and asthma, Kamangar said.

The review was published in the October issue of Cancer Prevention Research, a journal of the American Association for Cancer Research.