Why Tamoxifen fails to work on some breast cancer patients

British scientists have revealed that they have found why some women suffering from breast cancer do not respond to treatment by the drug Tamoxifen.

According to them, the drug is given to most women diagnosed with breast cancer to prevent the cancer returning, but not all of them respond to the drug, and experts estimate a third get no benefit.

The team of scientists in the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research say that the reason the drug does not work is because there is too much of a gene called FGFR1. This discovery could lead to new treatments for these women as scientists "switch off" the action of FGFR1.

They have already shown this is possible in the lab, after they introduced a drug, which "switched off" the action of FGFR1 enabling drugs like Tamoxifen to destroy cancer cells.

The researchers believe this could ultimately help thousands of women each year, as they say one in 10 breast cancer patients has too much of the FGFR1 gene.

"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 BBC quoted Dr Nick Turner, who led the research, as saying.

"There are a number of drugs in development that stop FGFR1 working, and clinical studies are investigating whether these drugs work against cancers with too many copies of this gene.

"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," he stated. Tamoxifen blocks the female sex hormone oestrogen that fuels the growth of some breast tumours.

"Cracking the problem of resistance to treatments such as Tamoxifen would be a major advance in treating breast cancer," Dr Lesley Walker of Cancer Research UK, the charity which helped fund the work, said.