Five new genes found that increase risk of breast cancer
10 May 2010
Five new regions of the genome that increase a woman’s risk of
developing breast cancer have been found by a team of researchers. The
researchers scanned the entire genetic code of 4,000 women with breast
cancer to find the genes.
These genes increase the risk of cancer by between six and 16 per
cent and take the total number of common ‘low risk’ genetic sites
associated with breast cancer to 18.
The study, published in Nature Genetics , was funded by Cancer
Research UK and the Wellcome Trust and carried out by scientists at
the University of Cambridge and The Institute of Cancer Research.
The increased risk conferred by these genetic variants is small.
But as more of these ‘low risk’ sites are found it may be possible
to create tests for a combination of them that together
significantly increase risk. This could help doctors make decisions
about prevention, diagnosis and treatment for women who are more
likely to get breast cancer.
One of the sites identified contains a gene called CDK2NA, which
regulates the process of cell division and is altered in the DNA of
many tumours. This gene has also been linked to increasing the risk
of a type of skin cancer called melanoma.
Interestingly, most of the regions found appear to predispose
predominantly towards oestrogen receptor positive breast cancers.
This could open new avenues for research into the use of drugs such
as tamoxifen, which can reduce the risk of this form of breast
The scientists scanned the entire genetic code of over 4,000
women with breast cancer and a family history of the disease for
genetic variations that cropped up more often compared to healthy
They then tested the most promising regions in over 12,000 women
with breast cancer, and 12,000 women without breast cancer, in an
Study author Professor Nazneen Rahman, Professor of Human
Genetics at 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.”
Lead author Professor Doug Easton, director of Cancer Research
UK’s Genetic Epidemiology Unit at the University of Cambridge, said:
“While each of these sites have a small impact on breast cancer
risk, by finding more of these genes we may be able to develop a
test that can predict more reliably a woman’s risk of developing
Breast cancer is the most common cancer in the UK with more than
45,500 new cases diagnosed each year. Lifestyle factors play an
important role in influencing the risk of breast cancer, but
inherited factors are also important in determining an individual
woman’s risk of the disease.
Dr Helen George, head of science information at Cancer Research
UK, said: "This is by far the largest study of its kind to explore
the common genetic variations that contribute to breast cancer risk.
This research takes us a step closer to developing a powerful
genetic test for the disease. Such a test could help doctors
identify women who have an increased breast cancer risk so that they
can make informed decisions about how to take steps to reduce their
chance of developing the disease."
Turnbull, C., et al. Genome-wide association study
identifies five new breast cancer susceptibility loci. Nature
Genetics 2010. Published online 9 May 2010. doi:10.1038/ng.586