An experimental drug that can virtually halt the deadly spread of breast cancer has been tested by scientists.
Researchers are now working with a biotechnology company to prepare the compound for patient trials.
The spread of tumours to vital organs such as the liver, brain and lungs, known as metastasis, is the chief reason why people die from cancer.
In the case of breast cancer, up to 12,000 British women a year develop metastatic disease, often several years after their initial diagnosis.
The new research builds on previous studies of a gene called Bc13 that appears to play a critical role in the spread of breast cancer.
Scientists at Cardiff University conducted computer simulations to work out how Bc13 functioned and then blocked it using a compound identified from a "virtual library" of chemicals.
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"We showed that suppressing this gene reduced the spread of cancer by more than 80%," said Dr Richard Clarkson from Cardiff University's European Cancer Stem Cell Research Institute.
"Our next goal was to then find a way to suppress Bcl3 pharmacologically. Despite great improvements in therapy of early stage breast cancer, the current therapeutic options for patients with late stage metastatic disease are limited.
"There is therefore a clear unmet clinical need to identify new drugs to reverse or at least to slow down disease progression."
In tests on mice, the researchers first deleted the gene and then explored ways of inhibiting it with a drug.
They found the right candidate compound by screening a library of chemicals until one was found that could target Bc13.
When mice with metastatic breast cancer were treated with the compound, the spread of tumours to the lungs and other parts of the body was dramatically reduced.
The team has now received financial backing from the UK-based biotech company Tiziana Pharmaceuticals to further develop the drug and bring it to clinical trials.