One in six women with a faulty BRIP1 gene are at risk of developing breast cancer by the age of 70, according to research published today.
Delegates at the National Cancer Research Institute conference, at the International Convention Centre in Birmingham, heard yesterday how this discovery could help identify women at risk of developing the disease, allowing early diagnosis.
Scientists at the Institute of Cancer Research, in London, studied the BRIP1 gene in 1,212 women who have a family history of the disease not due to known breast cancer genes BRCA1 and BRCA2, and compared them to 2,081 healthy women.
Nine BRIP1 faults were found in the breast cancer patients but only two in the healthy individuals, which indicates the gene is linked to breast cancer more often than would be expected by chance. The team worked out that carrying a faulty version of BRIP1 doubled a women's risk of the disease - taking their risk by the age of 70 from one in 12 to around one in six.
Inherited genetic faults are estimated to account for up to 25 per cent of familial breast cancer cases, and most of the damaged genes are still unidentified. Scientists decided to look at faults in the BRIP1 gene because it interacts with the known cancer causing gene, BRCA1.
Nazneen Rahman, professor of cancer genetics at the Institute of Cancer Research, said: "BRIP1 is the latest gene we have found and leads to a small increased risk of breast cancer.
"We know there are many more genes still to find before we have the complete picture of the genetic causes of breast cancer, but with each step we are making progress."
The study, published in today's Nature Genetics, reveals around 30,000 women - 0.1 per cent of the UK's population - carry a damaged version of the BRIP1 gene.
Like BRCA1 and BRCA2 it is a DNA-repair gene, so women with a faulty version of this gene cannot repair damaged DNA correctly, and therefore more likely to accumulate genetic damage that can trigger the cell to replicate uncontrollably, causing cancer.
Not all women with this faulty gene will develop breast cancer but researchers believe it contributes to around 100 new cases each year in Britain.
Professor John Toy, Cancer Research UK's medical director, said: "The discovery of a gene that increases breast cancer risk, even for a small number of women, is very important.
"Scientists are now beginning to understand more about the genes linked to breast cancer and we hope this will help identify and better manage more women at an increased risk of the disease." ..SUPL: