Iron-eliminating protein key factor in breast cancer: study

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WASHINGTON: A protein that eliminates iron from cells could be used to slow the growth of cancerous tumors, to treat breast cancer, and to predict the outcome for breast cancer patients, a study published Wednesday found.

Researchers at Wake Forest University Baptist Medical Center in North Carolina found that levels of ferroportin -- a protein that exports iron from cells -- are strikingly lower in breast tumors than in normal tissue.

The lack of ferroportin results in a build-up of iron, which allows a tumor to grow and perhaps become more aggressive, Suzy Torti, an associate professor of biochemistry at Wake Forest Baptist and one of the lead investigators on the study published in Science Translational Medicine, said.

When the researchers restored ferroportin levels to normal in human breast tumors in mice, the tumors grew more slowly.

"Because ferroportin can remove iron from the cell, when we put the protein back into the cell, the ferroportin removed the cancer's growth stimulus," said Torti.

"Our findings suggest that ferroportin is a substantial influence on the behavior of the cancer," she said.

Patients should not, however, change the amount of iron in their diets, she stressed, because the study was focused on cellular, not dietary iron.

The researchers also looked at data on more than 800 women with breast cancer to see if they could find a link between ferroportin levels and long-term outcomes for cancer.

They found that low ferroportin levels were a strong predictor of a poor outcome for women with breast cancer and that ferroportin levels were lowest in the most aggressive areas of cancer.

But they also had good news: high levels of ferroportin predicted a 90-percent chance that a woman would be a long-term cancer survivor.

"Using ferroportin as a marker for iron regulation may be a useful tool in breast cancer prognosis and may even help direct therapy," the study said.

"In the future, manipulating levels of ferroportin or proteins that affect levels of ferroportin may prove to be an effective breast cancer treatment," it said.