Breast Milk May Provide Method for Early Detection of Breast Cancer
Analysis of cells in a mother’s breast milk may yield earlier detection of breast cancer. According to researchers from the University of Massachusetts Amherst, examining breast milk may show signs of elevated breast cancer risk at an earlier age, especially among women who are not currently receiving mammograms or other screening. The research on the subject was recently presented at the 102nd annual meeting of the American Association for Cancer Research in Orlando, Florida.
According to lead researcher Kathleen Arcaro, because approximately 80 percent of women give birth at some point in their lives, a method of non-invasive testing such as that of analyzing breast milk for early indicators of heightened breast cancer risk could provide earlier screening than is currently available for the majority of women. In addition, screening would be available during pregnancy and lactation, which are times when diagnosing breast cancer can be difficult. Although other methods for assessing cancer risk such as ductal lavage and nipple aspiration are available, they are not only invasive, but also provide only tens to hundreds of cells for examiniation in comparison to the millions provided by collecting breast milk samples.
Through the analysis of the epithelial cells contained in breast milk, it may become possible in the future to assess the breast cancer risk of an individual mother. Epithelial tissues line the cavities and surfaces of structures throughout the body, and epithelial cells provide various functions including secretion, selective absorption, protection, transcellular transport and detection of sensation. The epithelial tissue layer lies on top of connective tissue joined by a membrane. This layer of tissue is composed of tightly clustered cells and receives nourishment from the underlying connective tissue, through the membrane. Therefore, the epithelial cells found in breast milk can harbor genetic changes that are linked to breast cancer.
For their study, the researchers collected breast milk samples from about 250 women undergoing breast biopsy (for tissue samples to be removed and sent for diagnostic testing to rule out the possibility of cancer occurrence). The scientists then tested DNA from breast cancer cells, searching for specific changes in three genes.
Among women whose biopsies revealed early signs of breast cancer, one of the gene types examined was found have been significantly altered by a process known as methylation. However, these altered genes were not found in the breast milk of women having low-risk, non-malignant breast abnormalities.
Arcaro noted that although their initial study was small it was “sufficient to tell us that we can use the cells in breast milk to assess breast cancer risk” and that further studies are now under way. She also pointed out that the key to breast cancer prevention is the early detection of methylation in breast tissue because methylation is reversible.
Arcaro further commented, “This in itself is not enough; we need to look at a larger panel of genes. But to find these methylation differences between biopsied and non-biopsied breasts when we only looked at three genes is very interesting and encouraging. We’re seeing differences not related to lactation or pregnancy. It clearly suggests that looking at a larger panel of genes would allow us to assess risk much more accurately, which leads to earlier detection of changes. A woman might be able to have her breast milk tested when she has a baby at age 25 or 30 and put her mind at ease, or give her an early warning.”
Almost 200,000 women are diagnosed with breast cancer each year, with over 40,000 dying from the disease annually. Although for now, a mammogram remains to be one of the best screening methods available for the early detection of breast cancer, Arcaro hopes that someday every woman who gives birth in a hospital will have her breast milk screened for cancer as a matter of course. If that day comes, she stated, “We’ll take a little sample of colostrum (milk produced in during the late stages of pregnancy), and we’ll tell her how her breasts are doing. It’s totally non-invasive, potentially inexpensive, and really accurate.”