Breast cancer patients could be encouraged to cut asparagus and other foods from their diets in the future to reduce the risk of the disease spreading, scientists say.
Researchers are investigating whether a change in diet could help patients with breast tumours after studies in mice showed that asparagine, a compound first identified in asparagus but present in many other foods, drives the spread of the disease to other organs.
When scientists reduced asparagine in animals with breast cancer, they found that the number of secondary tumours in other tissues fell dramatically. The spread of malignant cells, often to the bones, lungs and brain, is the main cause of death among patients who are diagnosed with breast cancer.
“This is a very promising lead and one of the very few instances where there is a scientific rationale for a dietary modification influencing cancer,” said lead scientist Prof Greg Hannon, director of the Cancer Research UK Cancer Institute in Cambridge.
Asparagine is an amino acid that is made naturally in the body as a building block for proteins. But it is also found in the diet, and in high levels in certain meats, vegetables and dairy products.
The international team of cancer specialists from Britain, the US, and Canada studied mice with an aggressive form of breast cancer. The mice develop secondary tumours in a matter of weeks and tend to die from the disease within months.
Writing in the journal Nature, the researchers describe how they reduced the ability of breast cancer to spread in the animals by blocking asparagine with a drug called L-asparaginase. To a lesser extent, by putting the animals on a low-asparagine diet worked too. Inspired by the results, the scientists examined records from human cancers and found that breast tumours that churned out the most asparagine were most likely to spread, leading patients to die sooner. The same was seen in cancers of the head, neck and kidney.