June 29, 2009

Gastrin’s role in stomach cancer defined

U.S. scientists say they've determined both an overabundance and a lack of the hormone gastrin play key rolls in bacterial-induced stomach cancer.

More than 50 percent of the world's population is infected with Helicobacter pylori, which is strongly linked to the development of gastric ulcers and stomach cancer, researchers said.

Helicobacter infection results in increased expression of gastrin, a hormone that stimulates secretion of gastric acid, However, the role of gastrin in cancer development remains unclear, scientists said. High levels of gastrin lead to the development of stomach cancer, but an absence of gastrin has been shown to increase the numbers of tumors in the gastric antrum, the lower section of the stomach.

To reconcile that apparent disparity, a group led by Dr. Timothy Wang at the Columbia University Medical Center examined the contribution of Helicobacter infection to gastric cancer in animal models.

The researchers said they found Helicobacter infection in mice with high levels of gastrin resulted in cancer in the main body of the stomach, whereas infection in gastrin-deficient mice developed cancer in a different part of the stomach, the gastric antrum.

Gastrin, the scientists said, therefore, plays a key role in the development of Helicobacter-induced stomach cancer, but may have distinct effects on carcinogenesis in different parts of the stomach.

The research is reported in the July issue of The American Journal of Pathology.