Breastmilk test may flag breast cancer risk early

Beginning this month and for the next year, environmental toxicologist Kathleen Arcaro of the University of Massachusetts Amherst will be recruiting subjects nationwide for a study to see if cells expressed in nursing mothers' breastmilk might one day provide a quick, easy way to assess a woman's future breast cancer risk.

Specifically, Arcaro and colleagues will be looking for methylated genes that indicate potentially pre-cancerous changes in breast cells. The test could show signs of elevated breast cancer risk in women at an earlier age than ever before - a population currently not receiving mammograms or other screening.

In fact, very few women of childbearing age might be expected to show age- or environment-related methylation, that is, chemical changes in certain genes, Arcaro acknowledges, but these changes do occur sporadically in younger women for unknown reasons. Once that happens and methyl groups attach to a gene and turn it off, all breast cells that later divide from the affected one will carry this dangerous defect into the following generations of cells. That's one reason it would be helpful to have an easy, non-invasive test at hand.

Researchers know that methylation pushes cells toward cancer development because they represent potential tumour sites, so the process is the focus of a great deal of study. There are a few new, targeted drugs available to reverse methylation by stripping methyl groups off of genes, making cells healthy once again. Thus, early detection of methylation in breast tissue is a key in preventing cancer, Arcaro says.

Other alternatives to mammography suitable for younger women exist for assessing breast cancer risk, the environmental toxicologist points out, but techniques such as ductal lavage and nipple aspiration yield very few cells, only tens or hundreds rather than the millions available from collecting breastmilk. Also, breastmilk contains what Arcaro calls 'a survey of cells from all the glands in the breast' rather than from only a few. This significantly extends the reach of the risk assessment to many more breast tissues than other methods.

Because breast cancer in young women is rare, Arcaro adds, 'the main advantage many women will get from our new test based on breast milk samples will be peace of mind.' But those few who are at elevated risk will find it out 'far, far earlier than ever before,' she adds, and the early warning should allow them to choose treatment options including demethylating drugs that are far less drastic than, for example, mastectomy.

The UMass Amherst study, funded by Congressionally Directed Medical Research Programs, is seeking to enroll a total of 500 nursing or breast-pumping mothers over the next year, women who have had a breast biopsy in the past or who are scheduled to have one soon. Interested women can contact the UMass Amherst research team online at www.breastmilkresearch.org. If they qualify to participate, they'll be mailed a breastmilk collection kit and asked to donate a sample, plus complete a questionnaire and consent form. Delivery and pickup of samples is free. Participants will receive $25 in appreciation for their time. Full confidentiality of medical records and other information is assured for all participants, Arcaro says.