Scientists have identified tiny fragments of DNA in breast milk that could one day help detect breast cancer earlier in new mothers.

Researchers at the University of Manchester, working at the National Biomarker Centre at the Christie, found that the DNA structure in breast milk is unique. They now understand what this DNA looks like, which they call a major step forward.

The study, funded by the Christie Charity, is initially recruiting 40 breastfeeding women, 25 at general population risk and 15 at higher risk because of family history. The aim is to build a biobank of more than 200 samples for future research.

Pregnancy-related breast cancer is thought to affect one in 3,000 pregnancies, but the risk can be as high as one in 50 for women carrying a faulty BRCA gene.

Dr Florent Mouliere, who leads the team analysing the samples, said the findings could eventually enable screening designed for pregnancy-related breast cancer.

The research is at an early stage, and the team stressed that much more work is needed before any test could be used in clinics.