Scientists Unlock Key to Tamoxifen Resistance
23 February 2010 - Scientists have discovered why some breast cancers are resistant to the commonly used drug tamoxifen. Women are commonly treated with tamoxifen for around five years after a breast cancer diagnosis, but some gradually develop resistance to the treatment.
The team of scientists in the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research (ICR) found that the resistance to tamoxifen and other hormone treatments occur when a gene called FGFR1 is turned on too much. Around a tenth of breast cancers have too much of the FGFR1 gene.
When stimulated in this way breast cancer cells no longer rely on hormones to grow rapidly and spread, making these hormone treatments less effective.
In lab studies the scientists were able to switch off FGFR1 in cancer cells with too much of the gene, by adding a drug that blocks the function of FGFR1. Once FGFR1 was switched off hormone treatments were once more able to work and destroy the cancer cells. Understanding more about switching off FGFR1 could lead to new treatments that benefit patients who do not respond to tamoxifen.
Lead author Dr Nick Turner said: “Understanding how this gene can cause tamoxifen resistance reveals a new drug target for treating breast cancers in patients who would otherwise have a poor outcome. The next step is to set up a clinical trial to see whether a drug that blocks the action of this gene can counteract hormone therapy resistance in breast cancer patients. If these trials confirm our lab work we could be on the verge of a potentially exciting new treatment for breast cancer.”
