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
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.