A New Marker to Spot Aggressive Breast Cancers?
Levels of a cellular protein seem to fall as tumor lethality rises, study finds
WEDNESDAY, Aug. 4, 2010 (HealthDay News) -- Low cellular levels of a protein known as ferroportin are tied to recurrent, aggressive breast cancers, new research suggests.
Testing levels of this protein, which eliminates iron from cells, may someday help doctors better predict which breast cancers will return and which need more intensive treatment, the researchers say.
"We had a hint that iron might be important in cancer in general, and particularly in breast cancer, but it hadn't been deeply studied," said Dr. Frank Torti, lead author of the new study and director of the Comprehensive Cancer Center at Wake Forest University Baptist Medical Center, Winston-Salem, NC.
Torti and his team report their findings online Aug. 4 in the journal Science Translational Medicine.
They first looked at isolated human breast cancer cells, finding a low level of the protein in breast cancer cells compared to normal breast cells.
Then, in a series of experiments, the team artificially boosted the protein to near normal levels in an aggressive breast cancer cell line. They found that the cancer cells grew much slower in the presence of added ferroportin.
The researchers also examined levels of the protein in human breast cancer tissue and found the lowest ferroportin levels occurring in the most aggressive cancers.
When they looked at gene activity profiles from more than 800 women included in four large study databases from around the world, the researchers found that decreased ferroportin gene expression is linked with a reduction in breast cancer survival. But high expression is linked with a favorable outcome -- namely, a 10-year survival of more than 90 percent.
The research is in early stages, but may eventually help doctors make a more accurate prognosis for breast cancer, using levels of ferroportin along with other markers such as tumor size and lymph node status, Torti said.
''One day, this discovery may lead to the development of a tissue test which can help predict recurrences based on ferroportin levels," he said. But for now, "we want to look at a larger group of women to confirm the results," Torti said.
"The initial studies they have done suggest this may be another way of predicting the behavior of breast cancer in additon to other available tests," added Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society. "However, as he [Torti] says, there is more research to be done." Whether the finding will prove to be clinically useful, he said, remains to be seen.
Another expert agreed. "If the findings bear out, testing for ferroportin might someday spare women from unnecessary treatments," said Susan Kane, professor of tumor cell biology at the City of Hope cancer center in Duarte, Calif.
"There is some thought that we overtreat, because it is difficult to determine [who needs which treatment to prevent recurrences]," Kane noted.
To learn more about breast cancer, visit the American Cancer Society.