Following the publication of a press release from the Breast Cancer Campaign, there has been a media flurry about the possibility of a blood test for breast cancer. This is based on a paper first published online in Cancer Research (and covered by FierceBiomarkers) in February, which pointed out that epigenetic changes (genetic changes that do not affect the DNA sequence) could be associated with the development of breast cancer.
Briefly, the researchers, led by Imperial College London (U.K.), used blood samples from 1,380 women at high risk of breast cancer and found an association between DNA methylation around a gene in white blood cells and the chance of developing breast cancer. The study found that women (particularly those younger than 60) with the highest levels of methylation in this region were twice as likely to go on to develop breast cancer as those with the lowest levels. The blood samples were taken an average of three (and up to 11) years before diagnosis.
Breast Cancer Campaign scientific fellow Dr. James Flanagan from Imperial College London said: "We know that genetic variation contributes to a person's risk of disease. With this new study we can now also say that epigenetic variation, or differences in how genes are modified, also has a role."
What has caught the media's (and the public's) attention is the idea that this could lead to a simple blood test for the risk of breast cancer in the coming decade. However, as the NHS Choices analysis says, it is far too early for that. This is only the first study to look at a large number of blood samples before diagnosis of the disease, and will need further validation. It also only looks at a single gene, and breast cancer, like many other disorders, is unlikely to be triggered by a single gene, so further genome-wide analyses will be needed. Even after all of this, the test is unlikely to be used in isolation but alongside genetic testing and risk-factor profiling. Nevertheless, the research could indeed contribute to a test for risk, not only for breast cancer, but also for a number of other cancers including leukemias and lymphomas, and so will be one to watch. Unlike what some of the media seems to be doing, though, don't expect it too soon.