Researchers find why some women are resistant to Tamoxifen

A prescription to buy Tamoxifen is one of the most effective treatments to prevent breast cancer from coming back. However, tumor cells can become resistant to the drug over time, diminishing its effectiveness. A team of University of California, San Francisco researchers may have found a solution to the problem.

They showed that women who have a certain genetic variation are more likely to develop a resistance to Tamoxifen. This abnormality results in the over-expression of a second gene known as AKT, which is responsible for cell survival and proliferation. In the case of breast cancer, this can encourage tumor cells to keep growing and spreading, despite being treated with Tamoxifen.

Fortunately, medications that suppress the AKT gene have already been developed. The researchers suggested that pairing this drug with Tamoxifen in individuals who have grown resistant may significantly increase the effectiveness of the medication.

"Understanding the mechanism of Tamoxifen resistance and how to defeat it may help a large number of women with hormone-resistant breast cancer," said lead researcher Pamela Munster. "It may lead quickly to new, more effective treatment strategies and may help to identify biomarkers to help to gauge whether or not someone will respond to treatment in the first place."