Breakthrough research has found an amino acid called asparagine plays a vital role in helping the disease move and restricting it stops cancer cells invading other parts of the body.
Scientists at the Cancer Research UK Cambridge Institute showed blocking its production with a drug called L-asparaginase in mice, and putting them on a low-asparagine diet, greatly reduced the breast cancer’s ability to spread.
The study is significant because most breast cancer patients do not die from their primary tumour but from the spread, or metastasis, of cancer to the lungs, brain, bones, or other organs.
To be able to spread cancer cells need to leave the original tumour, survive in the blood and then colonise other organs.
Professor Greg Hannon, lead author of the study, said: “Our work has pinpointed one of the key mechanisms that promotes the ability of breast cancer cells to spread.
“When the availability of asparagine was reduced, we saw little impact on the primary tumour in the breast, but tumour cells had reduced capacity for metastases in other parts of the body.
“This finding adds vital information to our understanding of how we can stop cancer spreading – the main reason patients die from their disease.
“In the future, restricting this amino acid through a controlled diet plan or by other means could be an additional part of treatment for some patients with breast and other cancers.”
Asparagine is an amino acid – the building blocks that cells use to make proteins.
While the body can make asparagine higher concentrations are found in foods including asparagus, soy, dairy, poultry, and seafood.
Latest data indicates the greater the ability of breast cancer cells to make asparagine, the more likely the disease is to spread. In several other cancer types, increased ability of tumour cells to make asparagine was also found to be associated with reduced survival.
Scientists now think that alongside conventional treatments like chemotherapy, breast cancer patients could be given a diet that restricts asparagine to help stop the disease spreading.
The findings also suggest this could have implications for other cancer types, including kidney, and head and neck.
Prof Charles Swanton, Cancer Research UK’s chief clinician, said: “This is interesting research looking at how cutting off the supply of nutrients essential to cancer’s spread could help restrain tumours.
“Interestingly, the drug L-asparaginase is used to treat acute lymphoblastic leukaemia which is dependent on asparagine.
“It’s possible that in future, this drug could be repurposed to help treat breast cancer patients.”
Martin Ledwick, Cancer Research UK’s head nurse, said: “Research like this is crucial to help develop better treatments for breast cancer patients.
“At the moment, there is no evidence that restricting certain foods can help fight cancer, so it’s important for patients to speak to their doctor before making any changes to their diet while having treatment.”
The research was published in the journal Nature.