Antioxidants Encourage Cancer in Some Cases, Study Says

Anil Ananthaswamy
for National Geographic News
August 19, 2009

Antioxidants, often praised for their reported cancer-fighting power, could in fact be aiding the growth of cancer in some situations, a new study says.

It's well known that in lab tests antioxidants—found in many vegetables and whole grains—can prevent the formation of tumors by preventing free radicals, or highly reactive molecules, from causing DNA damage.

Now, researchers have shown that antioxidants may have the opposite effect in human breast cells.

In a new experiment antioxidants behaved like cancer-causing agents, protecting cells that should otherwise have died—which allowed them to multiply and become cancerous.

"The survival of these cells could be contributing to [tumor creation], rather than the opposite," said study leader Zachary Schafer of the University of Notre Dame in Indiana.

Detached but Alive

Schafer and a team at Harvard Medical School cultured breast-tissue cells using a simulated scaffolding that mimics how cells grow in the body.

(Explore a human-body interactive.)

The cells formed a spherical structure that became hollowed out as the cells in the center detached from the cells on the scaffolding and died.

However, when the team introduced a cancer gene into the mix, the detached cells did not die—just as happens in the body.

"This happens in early breast cancer lesions," said Schafer, whose work was reported today online in the journal Nature.

The researchers, meanwhile, noticed that the normal, detached cells without the cancer gene were being damaged by naturally occurring free radicals.

Continued on Next Page >>


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