Discovery of new genetic clues to breast cancer

May 9 2010

By Candy Lashkari

Researchers at Cambridge University have identified five genetic clues for women who have a family history of breast cancer. The study brings up the number of common genetic variations linked to increased risk of breast cancer in women to 18. The study was published in  Nature Genetics.

Breast cancer is the most common form of cancer found in the UK with 45,500 new cases being diagnosed each year. It is also believed that one in 20 cases of breast cancer come from inherited faults in genes. Although environmental and lifestyle factors also play a role in the actual development of the disease.

The new research will make it easier to screen women with a family history of breast cancer for risk evaluation. The research scanned the genetic code of around 4,000 British patients with a known history of breast cancer in the family. This was later compared to the DNA of 24,000 other women who were both with and without the diagnosis of breast cancer.

Dr Douglas Easton of the University of Cambridge, who was the lead author of the study told the BBC, "We know for sure that these gene variations are associated with risk.It is not the whole picture but it will contribute ultimately to genetic profiling of risk"

The researching team found five spots on the human genome linked to a family history of breast cancer. Earlier 13 such spots had already been located. The two high risk genes that are likely to be defective in a person with breast cancer are known as BRCA1 and BRCA2.

"It also contributes to our understanding of why the disease develops and will lead to a better understanding of the biology of the disease." said Dr Douglas Easton. Having a close relative diagnosed with breast cancer can double the chances of a woman developing the disease.

The study also found that the women who had these new five spots on the genes were 16% more likely to develop the disease in their lifetime.The study conducted by the Institute of Cancer Research (ICR) was funded by Cancer Research UK and the Wellcome Trust.

Professor Nazneen Rahman, from the ICR, said, "Our results now take the total number of gene regions linked to the risk of breast cancer to 18, but we still don't know which genes are causing this increased risk. Identifying the underlying genes and mechanisms behind breast cancer development is essential to increasing our understanding of the disease and ultimately finding new treatments."

Dr Caroline Hacker, policy manager at Breakthrough Breast Cancer, said, "This could lead to new genetic tests which may help identify women who have an increased risk of breast cancer due to inherited faults in genes.Although there isn't anything we can do about the genes we inherit, we do know that you can reduce your risk of breast cancer by maintaining a healthy weight, limiting alcohol consumption and exercising regularly."