The Protective Effects of Estrogen

Stomach cancer more common in men than women

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Estrogen has been getting a bad name lately. The female hormone drives the most common form of breast cancer, but a new study suggests it also protects women from other types of cancer.

A recent study from the Massachussetts Institute of Technology (MIT) has demonstrated that estrogen may protect women from stomach cancer. Conversely, the lack of the estrogen hormone may be a reason why the cancer rates of this disease are dramatically higher in men.

"Estrogen research may lead to new stomach cancer therapies."

This new research was an animal study that describes how estrogen protects against stomach cancer. The hormone is particularly effective against cancers caused by Helicobacter pylori (H. pylori) bacterial infections.

These findings could lead to development of new drugs that target the disease -  possibly drugs that imitate the anti-cancer properties of estrogen.

The immune system controls infections caused by the bacteria H. pylori. This action, though, can lead to gastritis, which is chronic (ongoing) stomach inflammation. Gastritis, in turn, provides a favorable environment for stomach cancer.

It's thought that more than 50 percent of the world's population lives with this infection and doesn't know it. Most don't have any symptoms.

Previous studies have found that estrogen fights this type of inflamation, which accounts for why stomach cancer is less common in women than men. It followed then that women who are taking estrogen-blocking medications such as Tamoxifen to treat breast cancer may have increased risks of gastric cancer.

In this study, scientists worked with mice that had gastritis and also H. pylori infection. The male mice were treated with estrogen, Tamoxifen or both. The female mice received either Tamoxifen or nothing.

All groups of the treated male mice were protected against and none developed stomach cancer. Surprisingly, the female mice who received Tamoxifen showed no difference than the untreated female mice. So researchers figure that the Tamoxifen mimics but doesn't actually block estrogen in the stomach.

Alexander Sheh, a postdoctoral student in MIT’s Division of Comparative Medicine (DCM) and lead author of the paper, says being able to pinpoint the cause of this protection could lead to new therapies.

Researchers are now looking at the genetic reasons for why estrogen protects against stomach cancer.

This study was published online in the journal Cancer Prevention Research

Stomach cancer is the second-leading cause of cancer deaths worldwide. People who have the H. pylori infection are at greatest risk.

According to the American Cancer Society, an estimated 21,520 Americans will be diagnosed with stomach cancer this year - 13,120 men and 8,400 women. The disease will cause 10,340 deaths in the U.S.

Reviewed by: 
Review Date: 
July 24, 2011
Last Updated:
July 26, 2011