Scientists at the University of Manchester are examining whether circulating tumour DNA (ctDNA) found in breast milk could identify breast cancer earlier than a blood test or scan, in a potential breakthrough for early detection.
Study aims to improve detection during and after pregnancy
Breastfeeding is known to lower the risk of breast cancer in the long term, but women have a higher risk during pregnancy and after giving birth. Some women also carry genetic faults that place them at greater risk of developing the disease at a younger age.
Dr Niki Flaum, who is heading up the study and serves as a consultant oncologist at the Christie NHS Foundation Trust in Manchester, said: "There is an urgent need to find better, more reliable ways to detect breast cancer in women during and after pregnancy. We believe breast milk may provide a unique and non-invasive window into what is happening inside the breast."
"We know surprisingly little about the genetic changes to breast milk, as this bio-fluid has been remarkably under-researched until now," she added.
Pregnancy-related breast cancer often diagnosed late
Pregnancy-related breast cancer is more likely to be diagnosed at a later stage, when the cancer has already spread, and survival outcomes are significantly worse compared with women of the same age who have not recently given birth. Diagnosis is particularly challenging because breast imaging during pregnancy and lactation is often unreliable.
"If reliable methods for detecting cancer-related DNA in breast milk can be found, we hope future research will test whether this approach could be developed into a screening tool for women with breast cancer or those at high risk," Dr Flaum said.
Biobank to hold more than 200 samples
Breast cancer is the most common cause of cancer-related death among women aged 35 to 64 across the UK. Pregnancy-related breast cancer is believed to affect one in 3,000 pregnancies, though the risk can climb as high as one in 50 for those in higher-risk groups, such as women carrying a faulty BRCA gene.
The new study, backed by The Christie Charity, is initially recruiting 40 women who are producing breast milk – 25 from the general population and 15 from a high-risk category with a family history of breast cancer. The goal is to establish a Manchester Breast Biofluid Biobank containing more than 200 samples for future studies.
The University of Manchester team will examine the fluid samples at the National Biomarker Centre at the Christie.
Mothers share their motivation
Among the first mothers to donate breast milk for the trial was Hannah Brennan, 31, from Glossop in Derbyshire, who has a 12-month-old girl, Ada, alongside a five-year-old daughter and two-year-old son. A registered midwife currently studying for a PhD at the University of Manchester, she said: "As soon as I saw the research team were looking to recruit women who were breastfeeding, I wanted to do it."
"My paternal grandmother died aged 51 from breast cancer and sadly I never met her. However, I was named after her and I'm told I look like her so I'm doing this for her as well as my two daughters," she said. "Participating in the study was really straightforward. I just gave a blood sample and donated some breast milk and answered a few questions."
Dr Florent Mouliere, who heads up the research team examining samples, explained: "Scientists in our laboratories have identified tiny fragments of genetic material shed by cells in some samples of breast milk that have been donated for this study. The DNA structure is unique in breast milk, and we now understand what this DNA looks like, which is a major step forward."
Louise Hadley, chief executive of The Christie Charity, commented: "We are very pleased to be able to fund this important research which could improve early detection of breast cancer in high-risk women, including BRCA carriers, enable screening specifically for pregnancy-related breast cancer and help predict risk of postpartum breast cancer."
"It would also provide reassurance for high-risk women wishing to breastfeed, who are currently often advised to stop early so MRI screening can resume," she added. "This support is part of The Christie Charity's commitment to providing £30 million of much-needed funding by 2030 to enable our brightest researchers to make game-changing discoveries right here in Manchester."
