Breast Cancer
Nov. 12 (Bloomberg) -- Women who don't benefit from a drug used to prevent breast cancer recurrence may have low levels of a protein linked to improved survival, U.K. researchers found.
They also found that high levels of another protein could stop the drug tamoxifen from working as it should, according to a study online today in the journal Nature. Researchers said from 25 percent to 35 percent of women with breast cancer eventually develop resistance to the medicine.
Breast cancer is the most frequently diagnosed cancer in U.S. women, excluding cancer of the skin, according to the American Cancer Society. Determining why some women develop resistance to tamoxifen and others don't may help scientists develop better treatments for the disease, the researchers said.
``For the first time, we've started to identify what the key and critical factors are that can cause drug resistance,'' said study author Jason Carroll, a researcher at Cancer Research UK Cambridge Research Institute, in a Nov. 11 conference call with reporters.
Carroll said developing tests that doctors can use on a regular basis to determine if women have low levels of the protein, called PAX2, or high levels of a competing protein, known as AIB-1, are still at least five years away.
``This is a really interesting study. It certainly helps to supplement what we already know,'' said Eric Winer, an oncologist and director of the breast oncology center at Dana-Farber Cancer Institute in Boston in a Nov. 11 telephone interview. ``It is already being looked at in the clinic as a potential strategy to overcome resistance to hormonal therapy.''
Estrogen Receptors
About two out of three breast cancers grow because they are sensitive to the hormone estrogen, according to the American Cancer Society. Tamoxifen, a generic drug, temporarily blocks estrogen receptors on breast cancer cells and stops the...
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