Epigenetic changes act as DNA 'switches' allowing certain gene to become active or inactive. These changes can be affected by genetic mutations, such as the BRCA1 mutation, but also by environmental factors, such as exposure to chemicals, smoking, or drinking alcohol. The result is loss of healthy gene activity and disease development.
Scientists found that a particular pattern of epigenetic changes in the blood of women predisposed to develop breast cancer due to a faulty BRCA1 gene was also present in the blood of women who did not have the faulty gene but developed the disease.
Professor Martin Widschwendter, the study's lead author, from University College London, said: 'We identified an epigenetic signature in women with a mutated BRCA1 gene that was linked to increased cancer risk and lower survival rates. Surprisingly, we found the same signature in large cohorts of women without the BRCA1 mutation and it was able to predict breast cancer risk several years before diagnosis'.
BRCA1 and BRCA2 mutations, passed down by a parent, are the cause of about ten percent of breast cancers, with the other 90 percent of cases being non-hereditary and unexplained.
Women who carry a BRCA1 mutation have an 85 percent risk of developing breast cancer, a chance that often leads them to the drastic solution of an early mastectomy.
Dr Matthew Lam, senior research officer at the Breakthrough Breast Cancer charity said: 'These results are definitely promising and we're excited to learn how further research could build on these findings'.
'This could mean that in the future a woman may be able to have a simple blood test to look for this DNA signature, and therefore know if she is at a higher risk of developing breast cancer. If she does have this signature, she could then work with her doctor to explore the options available to help her take control of her own risk'.
The proportion of women at high risk of developing breast cancer who have this epigenetic signature remains unknown. But the idea of a blood test that would be able to reliably predict whether non-hereditary breast cancer will develop is an exciting prospect.
'DNA signatures such as this have the potential to add an extra layer of accuracy in the way we are able to assess a woman's individual risk of breast cancer and we are eager to learn more in this area', Dr Lam added.