FATAL breast cancer can be diagnosed up to 1 year earlier than current diagnosis methods by finding a region of DNA in the blood, according to researchers from University College London, London, UK. It is hoped that establishing the presence of the DNA methylation marker EFC#93 could lead to early individualised treatment methods before the cancer becomes detectable in the breast.
In the study, the authors first analysed EFC#93 in blood serum samples from 419 women already diagnosed with breast cancer, and then from 925 healthy women. In the breast cancer patient cohort, the samples were taken at two time points: after surgery but before the start of chemotherapy, and following completion of chemotherapy. It was found that pre-chemotherapy, aberrant DNA methylation was an indicator of poor prognosis, independent of the presence of circulating tumour cells.
In the healthy women, the presence EFC#93 correctly detected 43% who were diagnosed with fatal breast cancer 3–6 months after giving serum samples, and 25% of whom were diagnosed with the condition 6–12 months later. This marker also identified 88% of women who did not later develop breast cancer. Additionally, EFC#93 did not identify non-fatal breast cancers early; thus, this method could potentially also avoid overdiagnosis, a significant issue with regards to mammography screening.
Corresponding author Prof Martin Widschwendter, University College London, commented: “For the first time, our study provides evidence that serum DNA methylation markers such as EFC#93 provide a highly specific indicator that could diagnose fatal breast cancers up to 1 year in advance of current diagnosis. This may enable individualised treatment, which could even begin in the absence of radiological evidence in the breast.”
The authors acknowledged that the study is limited because of the lack of samples that contained large amounts of background DNA, thus making it difficult to detect large amounts of tumour DNA. They also stated that clinical trials are now needed to ascertain whether women who are EFC#93 positive and do not have cancer discoverable by mammography would benefit from anti-hormonal therapy before the cancer is detectable in the breast.
James Coker, Reporter
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