July 7 (HealthDay News) -- A compound found in red grapes and red wine suppresses abnormal cell formation that leads to most types of breast cancer, according to U.S. researchers.

The compound, resveratrol, is sold in extract form as a dietary supplement.

Breast cancer forms through a multi-stage process that differs depending on the type of disease, a person's genes, and other factors. However, it's known that increased estrogen fuels many types of breast cancer.

"Resveratrol has the ability to prevent the first step that occurs when estrogen starts the process that leads to cancer by blocking the formation of the estrogen DNA adducts. We believe that this could stop the whole progression that leads to breast cancer down the road," study author Eleanor G. Rogan, a professor in the Eppley Institute for Research in Cancer and Allied Diseases at the University of Nebraska Medical Center, said in a prepared statement.

In laboratory testing, Rogan and her team found that as little as 10 umol/L of resveratrol could suppress DNA adducts associated with breast cancer. A glass of red wine contains between 9 and 28 umol/L of resveratrol.

Rogan and colleagues also found that reseveratrol suppressed expression of CYP1B1 and the formation of 2,3,7,8-Tetrachlorodibenzo-p-dioxin, two known risk factors for breast cancer.

Resveratrol induces an enzyme called quinone reductase, which reduces the estrogen metabolite back to inactive form and reduces breast cancer risk, Rogan explained.

The findings, which are in the July issue of Cancer Prevention Research, will have to be confirmed in human trials, she noted.

SOURCE: American Association for Cancer Research, news release, July 7, 2008