Breast milk may eventually be used to assess breast cancer risk.

“It looks as if we can use the cells from breast milk to assess breast cancer risk,” said Dr. Kathleen Arcaro, an associate professor of veterinary and animal sciences at the University of Massachusetts in Amherst.

By screening breast milk for cells that can turn into cancer, researchers believe they can develop a way to warn women if they’re at an increased risk of developing breast cancer later in life. Results from the new study were presented Monday at the American Association for Cancer Research in Orlando.

Milk samples were selected from 271 women, one sample from each breast. The women also underwent a breast biopsy, the most definitive way to tell if a woman has breast cancer.

By evaluating the biopsied and non-biopsied samples, Dr. Arcarao isolated potentially cancerous cells, known as epithelial cells.  These cells line the inside of the breast and are most likely to turn into tumors.

Next, researchers isolated DNA of those cells that are known to play a role in breast cancer. They looked for epigenetic signals on the genes, signals that tell the body to “turn on” these genes.

Among the women diagnosed via biopsy with a tumor in one breast, researchers found a significant increase in epigenetic signals for the gene RASSF1 in the milk from that breast, compared with milk from the breast that wasn’t biopsied.

The researchers believe that signal is significant enough to warrant screening for women. Further studies should analyze changes in other genes, says Arcaro.

A long-term study is underway with 80% of the women in the original study. 

It’s too soon to assess the cancer detection rate associated with breast milk cell examination, Dr. Arcaro said, but research is continuing.