Breast cancer drug 'breakthrough'

Scientists believe they have made a breakthrough in a treatment for breast cancer. Some women using the anti-cancer drug tamoxifen have found it stopped working. Now researchers at Tenovus Centre for Cancer Research at Cardiff University say they have found a way to halt or even reverse resistance to the drug.

The research centre said the discovery could provide a huge boost to patients fighting the disease. Scientist have discovered that by inhibiting the activity of a certain chemical in cancer cells, tamoxifen continues to work.

The chemical is a protein known as Src, and researchers have found it is more active in laboratory grown breast cancer cells.

But as part of research with the medical giant AstraZeneca, the Tenovus centre found it could treat cancer cells with a new drug which halted the Src protein. The drug, which is now in very early clinical trials, is known for now by its lab name of AZD0530. Used along with tamoxifen, scientists say that in laboratory trials it appears to prevent and even reverse resistance to the anti-cancer drug.

Prof Robert Nicholson, director of the Tenovus Centre for Cancer Research, said it was an important milestone in their research. "Whilst little is known about the mechanisms used by breast cancers to become resistant to common therapies such as Tamoxifen, it remains a significant clinical problem," he explained. "Therefore the ability to restore sensitivity to therapy, or to even prevent resistance arising in the first place, could be of huge benefit to a large number of breast cancer patients."

Tamoxifen is one of the main drugs used to tackle hormone-sensitive breast cancer, and is usually taken by patients for five years to prevent the disease returning. It can also be used to treat women at high risk, with studies estimating that the drug can cut the risk of developing hormone-sensitive breast cancer by more than a third.