Examining the epithelial cells present in breast milk may help to evaluate a woman’s breast cancer risk, according to a study conducted at the University of Massachusetts Amherst in the US.

Researchers collected breast milk samples from both breasts 250 women from across the country who were scheduled for breast biopsy or who had already undergone the surgery.

The research team looked for evidence of an epigenetic response called methylation in three genes — RASSF1, GSTP1 and SFRP1 &#151 among the approximately 35 genes known to be methylated in breast cancer.

In the first analysis, which involved 182 women, researchers found that the top 5-8% of women who had biopsies had a greater methylation, compared to a group of healthy women.

In the second analysis, researchers compared methylation levels in cells from biopsied versus non-biopsied breasts, and found that biopsied breast samples had greater methylation.

They added that this methylation indicates that the helpful, tumour-suppressing genes are silenced, putting the woman at higher risk of developing breast cancer.

Study author Kathleen Arcaro said it wass interesting to find the methylation differences between biopsied and non-biopsied breasts when only three genes are analysed.

“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,”

Researchers are conducting studies to expand the number of genes and to further develop the test.