Cancer risk becomes clearer

Breast cancer is one of the biggest killers

Scientists say they are close to pinpointing exactly why some women are more susceptible to breast cancer than others.

When breast cancer runs in families it is often due to a fault in one of the breast cancer genes BRCA1 and BRCA2.

This difference helps us to understand why the risk is greater and might lead to an alternative to surgery for women who have a BRCA mutation

Dr Rob Clarke

These women have up to an 80% risk of the disease and often opt for preventative surgery.

A team from the Paterson Institute for Cancer Research in Manchester has found that there is a crucial difference between normal breast tissue from women with a BRCA mutation and tissue from women at normal risk.

They believe that understanding these differences may eventually lead to preventative drugs as an alternative to surgery.

The difference between the women seems to lie in the way their cells respond to the hormone oestrogen and to anti-oestrogen drugs, such as Tamoxifen.

Subtle difference

Dr Lesley Walker believes the work is significant

Lead researcher Dr Rob Clarke said: "When we added oestrogen to the breast tissue we expected a bigger response from the BRCA cells, we thought they would grow faster than the normal cells but this didn't happen.

"Instead we found a far more subtle difference in the way other genes were responding to oestrogen.

"This difference helps us to understand why the risk is greater and might lead to an alternative to surgery for women who have a BRCA mutation."

Dr Clarke believes that the BRCA mutations have a direct effect on the genes that control the way breast cells mature.

It is known that women who become pregnant in their early twenties are less likely to develop breast cancer than women who do not have children.

Nuns

As long ago as the 19th century it was noted that nuns were more likely to develop breast cancer than women who had several children.

Scientists believe this is because pregnancy accelerates the maturation of the breast cells, enabling them to produce milk.

They believe that matured cells are much less likely to become cancerous because they are less likely to start dividing in an uncontrolled way.

The BRCA mutations may act to block this process of maturation.

Dr Lesley Walker, Cancer Research Campaign Director of Cancer Information, said: "It's important to find out which women are at a high risk of breast cancer and why.

"But if we're going to do that, it's equally important that we can offer these women treatment to prevent the disease.

"There's still a long way to go but this work brings us closer to drugs or treatments to prevent the disease."