Test predicts risk of breast cancer years in advance
A simple blood test which predicts a woman's likelihood of suffering breast cancer is being developed by scientists.
For the first time, researchers have identified a way of discovering whether a woman is at risk even if she has no genetic predisposition.
Within five years, they hope to develop a test which can predict the danger of breast or ovarian concern for up to a decade ahead.
Experts said last night the findings were a "promising" and exciting prospect, which could in future help protect women.
The study, by scientists at University College London, found that women who developed hereditary breast cancer, caused by a BRCA1 mutation, had the same changes to molecules in their blood as others who developed the disease despite having no genetic predisposition. The changes were found years before diagnosis.
Around 10 per cent of breast cancers are caused by BRCA1 and BRCA2 gene variants inherited from parents, but the rest are unexplained. Until now there has been no reliable way to predict a likelihood of non-inherited breast cancer.
The "switch" discovered by scientists is part of a process that cause genes to be turned on or off. It is influenced by factors including alcohol and smoking, so women who knew they were more likely to develop breast cancer could adopt changes to their lifestyle, experts said.
The changes could be detected in blood samples years before symptoms develop, the study suggests.
Professor Martin Widschwendter, the lead researcher, 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."
Dr Matthew Lam, senior research officer at the charity Breakthrough Breast Cancer, said: "These results are definitely promising and we're excited to learn how further research could build on these findings."
He added: "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."
What proportion of women at higher risk of breast cancer have the epigenetic marker is unknown. The scientists analysed blood sample DNA from 119 post-menopausal women who went on to develop breast cancer over a period of up to 12 years, and 122 who remained cancer-free.
Their results appear in the online journal Genome Medicine. (© Daily Telegraph, London)