Study Explains Why Men Are At Higher Risk For Stomach Cancer

Several types of cancer, including stomach, liver and colon, are far more common in men than in women. Some scientists have theorized that differences in lifestyle, such as diet and smoking, may account for the discrepancy, but growing evidence suggests that the differences are rooted in basic biological differences between men and women. Adding to that evidence, a new study from MIT shows that treating male mice with estrogen dramatically lowers their rates of stomach cancer — specifically, cancers caused by chronic infection by the bacterium Helicobacter pylori.

The paper, which recently appeared online in the journal Cancer Prevention Research, also describes in new detail how estrogen protects against gastric cancer, which could help scientists find better drug targets against the disease.

It's unlikely that doctors would treat men with estrogen, but the researchers believe their work could lead to treatments that mimic estrogen's cancer-suppressing effects. "If we can narrow in on which estrogen effect is causing this protection, we can come up with a better therapy," says Alexander Sheh, a postdoc in MIT's Division of Comparative Medicine (DCM) and lead author of the paper.

Gastric cancer is the second-leading cause of cancer deaths worldwide, and people infected with H. pylori are much more likely to develop gastric cancer than uninfected people. More than 50 percent of the world's population is infected, though most do not experience any symptoms.

H. pylori infection provokes an immune response that keeps the infection under control but can lead to gastritis, a chronic inflammation of the stomach that is conducive to the development of gastric cancer.