Broccoli could be the key to preventing "fatal" tumours such as head and neck cancer, according to scientists.
Researchers in the US found that broccoli sprout extracts could prevent oral cancer in mice. They then extended the test to a small group of healthy human volunteers, with promising results.
Now researchers hope to extend the trials to those at high risk of recurrence from head and neck cancer, by giving them capsules containing broccoli seed powder.
"People who are cured of head and neck cancer are still at very high risk for a second cancer in their mouth or throat, and, unfortunately, these second cancers are commonly fatal," said lead author Julie Bauman, co-director of the UPMC Head and Neck Cancer Center of Excellence.
"So we're developing a safe, natural molecule found in cruciferous vegetables to protect the oral lining where these cancers form."
Over a period of several months, scientists gave sulforaphane - often found in vegetables such as broccoli, cabbage and garden cress - to mice who were predisposed to oral cancer.
They discovered that it significantly reduced the number of tumours.
Now, researchers from the University of Pittsburgh Cancer Institute hope to test the theory further in a human clinical trial, which will recruit participants at high risk for head and neck cancer recurrence.
Previous studies found that cruciferous vegetables that have a high concentration of sulforaphane help to reduce the potentially damaging effects of environmental carcinogens.
"The clear benefit of sulforaphane in preventing oral cancer in mice raises hope that this well-tolerated compound also may act to prevent oral cancer in humans who face chronic exposure to environmental pollutants and carcinogens," said Dr Johnson, professor of medicine at University of Pittsburgh Cancer Institute and a senior scientist in the UPCI Head and Neck Cancer Program.
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Since the successful study on mice, Dr Bauman treated 10 healthy human volunteers with fruit juice mixed with sulforaphane-rich broccoli sprout extract.
The volunteers had no negative side effects from the extract and protective changes were detectable in the lining of their mouths, meaning it was absorbed and directed to at-risk tissue.
The scientists now hope to implement a clinical trial of 40 volunteers with head and neck cancer.
The participants will regularly take capsules containing broccoli seed powder to determine if they can tolerate the regimen and whether it has enough of an impact on their oral lining to prevent cancer.