A blood test could offer many women an early warning of breast cancer even if they do not inherit the high-risk BRCA1 gene mutation, according findings published today.
A research team led by BRC-supported Professor Martin Widschwendter, from the UCL Department of Women’s Cancer, identified a molecular "switch" in blood samples that increases a woman's chances of having breast cancer.
The marker is associated with the BRCA1 gene, but was also found in women without the mutation who developed the disease.
The BRCA1 gene is associated with an 85% risk of developing breast cancer. However there has been no reliable way of predicting the likelihood of non-inherited breast cancer until now.
In this study researchers analysed blood sample DNA from 119 postmenopausal women who went on to develop breast cancer over a period of up to 12 years, and 122 who remained cancer-free.
They looked at the epigenetic signature of those with BRCA1 mutations and compared them to those without. When the signature was compared to samples from both cohorts those women who developed non-hereditary cancers were found to have the same methylation pattern (a common epigenetic signalling tool that cells use to lock genes in the "off" position), and this is what the team believe could help predict risk in the future.
Professor Widschwendter 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 many years before diagnosis.”
The researchers believe the epigenetic signature they found is consistent with the idea that changes in the epigenome of immune cells can influence cancer progression and the signature may be responsible for silencing genes in immune cells. This silencing could affect the immune system’s ability to prevent breast cancer development.
Further research needs to be done to find out whether this epigenetic signature is just an indicator of breast cancer risk or is involved with the progression of breast cancer. Work is now proceeding on using these findings in the clinical setting.
Professor Widschwendter went on to say: “We have developed a new test for breast cancer risk in women. We demonstrated the technique using blood samples, but it could be even more effective when applied to cheek or cervical swabs. This has the potential to predict breast cancer risk far better than current screening tools. We are now using this technique to develop clinical tests to predict the risk for both breast and gynaecological cancers.”
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