How breast cancer gene increases risk factor

Angelina Jolie has explained why she chose to have a double mastectomy earlier this year, in an article she wrote for the New York Times.

The actress says she was told she had an 87% chance of developing breast cancer because of a BRCA1 gene mutation she carries.

Professor Gareth Evans, clinical geneticist and director of the Manchester Breast Centre, told the BBC the risk of developing cancer is not down to the gene alone, but lifestyle and health as well:

"It does depends on other risk factors. The risk for someone with a BRCA1 mutation could vary between 50 and 95%."