In a small study, researchers have identified protein biomarkers for breast cancer using breast milk, a discovery that they believe is the first step towards developing a simple blood test to screen patients faster and more easily.

The research, which is being presented at the American Society for Biochemistry and Molecular Biology annual meeting during the Experimental Biology 2022 conference this week, compared the breast milk of three women with breast cancer to milk from three who did not have any breast cancer.

They found that between the two sets of samples, there were 23 proteins that differed and all of them were proteins that had been previously linked to cancer or tumour development.

Isolating biomarkers to look for puts them closer to developing a blood test that could be taken easily to screen for breast cancer, the researchers note.

“Although mammograms are a useful tool for catching breast cancer early, they aren’t typically recommended for low-risk women under 40,” Danielle Whitham, a doctoral candidate at Clarkson University in New York, and lead author of the research, said in a press release. “Because the biomarkers we found in breast milk are also detectable in blood serum, screening could potentially be done in women of any age using blood or breast milk.”

It’s well known that when it comes to battling cancer, early identification is key to a higher chance of beating the disease.

“If our future studies are successful, it could change how women are monitored for breast cancer and aid in earlier diagnosis,” Whitham said. “This could even lead to a higher survival rate in women.”

In order to isolate the proteins, researchers broke the ions in the breast milk down to fragments, using a process called tandem mass spectrometry, which allows scientists to see the chemical structures that make up the substance.

In the women with breast cancer, there were 23 proteins that were dysregulated, meaning that there were unexpected changes in how those proteins were being synthesized, leading to changes in cellular structure. Previous research has found that dysregulated proteins is a sign of various conditions, including cancer.

“We used breast milk because it contains proteins, epithelial cells and immune cells, all of which provide a great deal of information about what is happening in a woman’s body during a crucial time in breast development,” Whitham said.

The set of biomarkers that researchers identified only apply to one type of breast cancer: invasive duct carcinoma (IDC), which is one of the most common types.

But researchers believe that as they research further, they could uncover more biomarkers for other types of breast cancer.

The next step is to replicate their results with a larger group of participants, in order to confirm the biomarkers. Any women producing breast milk who are interested in helping out with future studies are encouraged to reach out to donate samples.

If the protein biomarkers are confirmed in a larger study, researchers will test for these biomarkers in blood serum in order to start the journey towards a blood test that could change the breast cancer screening process.