London School of Hygiene & Tropical Medicine

Scientists have discovered a new area of the genome associated with breast cancer risk. This new area (locus) lies within a "gene desert" - a region of the genome that lacks identifiable genes.

The latest risk area occurs on chromosome 9 - specifically 9q31.2 - which is the sixteenth region of the genome shown to be associated with a modest breast cancer risk. Looking at this loci in isolation shows a 10% change in risk which can be deemed modest as there are many factors that affect a person's chances of developing breast cancer not just this single area of the genome. The results are published in the National Journal of the Cancer Institute (JNCI).

Breast cancer is the most commonly diagnosed cancer in the UK, with nearly 48,000 women developing the disease each year, and one in eight affected during their lifetime. Study author Professor Julian Peto, from the London School of Hygiene and Tropical Medicine, said: "This is an exciting new finding which will help us to understand how breast cancer develops. As yet we do not know the mechanism by which this gene desert affects breast cancer risk, but it is an area of active research. Women should not be concerned by these findings because the impact of this area of the genome on breast cancer risk is very small."

This study analysed genetic information from women participating in the Breakthrough Generations Study, the British Breast Cancer study and the Family History study. The findings are the first genetic discovery to come out of the Breakthrough Generations Study and although the development will not have an immediate impact on patients with breast cancer, in the longer term, this type of discovery could allow for more personalised treatment.

The scientists, funded by Breakthrough Breast Cancer and Cancer Research UK, first screened blood from 1700 patients with breast cancer, most of whom were women who had had two independent primary breast cancers. From this screen they produced a shortlist of 1200 genetic variants that were taken forward for further study. It was one of these - at 9q31.2 - that was found to be a novel locus associated with breast cancer risk. Scientists believe there may be many more areas of the genome of this kind. These additional areas will need to be identified and research into the specific roles they play carried out to understand how genes work in combination affect breast cancer development.

Dr Julia Wilson, Head of Research at Breakthrough Breast Cancer, said: "This research provides one piece in the puzzle of how our genes affect our risk of developing breast cancer. Unravelling the exact causes of breast cancer is a difficult task which will take time but it's exciting that the Breakthrough Generations Study is helping us do that. This is a positive step towards a future free from the fear of breast cancer."

Breast cancer does not have a single cause and the risk of developing breast cancer is a combination of many different genetic, environmental and lifestyle factors. Researchers still have much to learn about the genetic and environmental factors and how they interact with each other but discoveries such as this may help scientists to understand how we can reduce the risk of breast cancer and move into an era of personalised medicine.

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For more information, please contact Richard Purnell or Sarah Viner in the Breakthrough Breast Cancer Press Office on 020 7025 2432, or Paula Fentiman at the London School of Hygiene & Tropical Medicine on 020 7927 2802 or email paula.fentiman@lshtm.ac.uk.