Researchers have developed a test that shows whether breast cancer patients will benefit from the anti-hormone drugs tamoxifen and anastrozole.

Thirty per cent of women given tamoxifen to prevent breast cancer do not benefit from it. Tamoxifen, and the related drug anastrozole, work by blocking the hormone estrogen. This is beneficial, but only for women whose tumors are estrogen-responsive.

The new test, developed by researchers in London, can detect whether breast cancer cells are estrogen-responsive or not. The test includes a gene which produces a yellow color in contact with estrogen-receptive elements, which makes it easy to read. Once it is ready for use in patients, it can be used not just to select women who'll respond to the estrogen blockers, but also to monitor their treatment.

Source

International Journal of Cancer October 2003 Volume 107 pages 700-706