A person’s risk of breast cancer could be decided many years before it develops, according to experts.

Breast Cancer Campaign scientific fellow, Dr James Flanagan, from Imperial College London has uncovered the first strong evidence that molecular or ‘epigenetic’ changes in a gene can be associated with breast cancer risk and can be detected many years before breast cancer develops. Dr Flanagan’s latest findings could also have important implications for predicting risk in other cancers, as the ATM gene highlighted in his study has been linked with a number of other cancers, including lymphoma and leukaemia.

The research, which was funded by Asda’s Tickled Pink campaign and is published in the May issue of  Cancer Research, tested 1,380 women and is the first to look at a large number of blood samples before diagnosis of the disease to find out whether the alteration of single genes by a process called methylation can predict whether women have an increased breast cancer risk.

Dr Flanagan found that, of the 1,380 women tested those with the highest amount of methylation were twice as likely to get breast cancer as women with the lowest amount on one area of a gene called ATM. This result was particularly clear in blood samples taken from women under the age of 60.

Importantly, because this is the first study using blood taken on average three years before diagnosis and in some cases up to eleven years, it shows that the genes were not altered because of active cancer in the body or by treatments for cancer, which has been a problem with previous studies that took blood after diagnosis.

These findings provide strong evidence that looking at this type of epigenetic alteration (methylation) on individual genes could be used as a blood test to help assess breast cancer risk. When used in combination with other risk assessment tools such as genetic testing and risk factor profiling, this simple blood test could identify those at higher risk, helping doctors to monitor and one day maybe even prevent breast cancer ever developing.

The findings now need rigorous testing in many more individuals and many more genes that contribute to a person’s risk profile need to be identified, as this is just one gene that makes up a small component.

Epigenetics research is changing the way scientists think about genes and their development and so could play an important role in helping to prevent cancer. It was previously thought that only errors in the fundamental genetic information from our DNA - whether inherited or caused by environmental factors - determined whether our cells become cancerous. However, new research is showing how chemical modifications to DNA, that control our genes, could be even more important than our DNA alone in determining how our cells grow.

Dr Flanagan said, “We know that genetic variation contributes to a person’s risk of disease. With this new study we can now also say that epigenetic variation, or differences in how genes are modified, also has a role.

“We hope that this research is just the beginning of our understanding about the epigenetic component of breast cancer risk and in the coming years we hope to find many more examples of genes that contribute to a person’s risk. The challenge will be how to incorporate all of this new information into the computer models that are currently used for individual risk prediction. 

“So far we have found alterations in one small region of a gene that appear to associate with risk of disease and so the next step with this epigenetic research is a genome wide approach to try and find all the associated genes.”

Baroness Delyth Morgan, Chief Executive, Breast Cancer Campaign said, “Dr Flanagan’s research into epigenetics is so exciting because it suggests that there is every possibility the risk of developing breast cancer could be decided many decades in advance. By piecing together how this happens, we can look at ways of preventing the disease and detecting it earlier to give people the best possible chance of survival.”