Eighty percent of women give birth, and now there may be a chance that breast cancer can be detected earlier by examining cells in breast milk, according to a presentation at the American Association for Cancer Research 102nd Annual Meeting in Orlando, Florida this week.
Analyzing the epithelial cells may in future make it possible to assess an individual mother's risk, researchers believe. Epithelial cells are joined together by cell junctions (tight junctions found only in epithelia, but also adhering junctions and gap junctions, which are found also in other tissues). The epithelial cell layer is attached to the underlying connective tissue by a basement membrane, which is secreted in part by the epithelial cells and the underlying connective tissue cells.
Kathleen Arcaro of UMass Amherst says that because about 80% of women give birth, non-invasively testing their breast milk for early indicators of elevated breast cancer risk would provide screening for a majority of women earlier than currently available and at a time (during pregnancy and lactation) when it is difficult to diagnose breast cancer. Other methods of obtaining breast cells to assess cancer risk in women of all ages exist, but techniques such as ductal lavage and nipple aspiration are invasive and yield very few cells, only tens or hundreds rather than the millions available from collecting breast milk.
Early detection of methylation in breast tissue is a key in preventing cancer, Arcaro notes, and is the focus of a great deal of study. Epigenetic changes are not related to DNA mutations, and are often thought to be related to environmental exposures. They are passed on to dividing cells. However, methylation is reversible, so early detection increases treatment options.
DNA methylation is essential for normal development and is associated with a number of key processes including genomic imprinting, X-chromosome inactivation, suppression of repetitive elements, and carcinogenesis.
"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."
Examining breast milk could show signs of elevated breast cancer risk in women at an earlier age than ever before, in a population currently not receiving mammograms or other screening. More studies are needed to expand the number of genes, and long-term studies are now underway with about 80% of the original participants enrolled in long-term follow-up.
Arcaro continues regarding the next phase of research:
"We'll take a little sample of colostrums, and with a totally noninvasive and accurate assay, be able to tell her how her breasts are doing."
A mammogram, or X-ray of the breast, is still one of the best tools available for the early detection of breast cancer. It cannot cause cancer to spread, nor can the pressure put on the breast from the mammogram.
Source: University of Massachusetts Amherst
Written by Sy Kraft, B.A.