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'Abortion pill' ingredient stalls growth of breast cancer: research

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The main ingredient in the RU486 abortion pill can suppress the growth of breast cancer tumors, a new study released Thursday said.

Mifepristone, the main active compound in the controversial French-developed abortion pill, can prevent breast tumors by inhibiting progesterone in breast tissues, scientists at the University of California at Irvine found.

Researchers led by cell biologist Eva Lee tested the effects of mifepristone on mice which carried a mutated gene, BRCA-1, the presence in women of which is closely linked with breast and ovarian cancers, according to a summary of the research.

They knew that mifepristone worked to halt pregnancies in the first trimester by blocking progesterone, a hormone secreted by the ovaries that is important to female reproduction.

They also knew that earlier research linked high progesterone levels in women to increased risk of breast cancer.

In research on mice with the mutated BRCA-1 gene, they showed that the presence of progesterone increases the multiplication of cancer cells.

When the mice were treated with mifespristone, though, the compound effectively blocked progesterone from inciting the cell division that leads to cancer tumor growth.

Together with other research, the findings suggested that anti-progesterone treatment could help prevent the development of breast cancer in women at risk of the disease.

"We're excited about this discovery and hope it leads to new options for women with a high risk for developing breast cancer," Lee said in a statement.

The new study will be published in the December 1 edition of the journal Science.



AFP 302122 GMT 11 06

COPYRIGHT 2006 Agence France-Presse. All rights reserved.

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