Botox injections could provide an effective new treatment for stomach cancer, research has shown.
The rejuvenating anti-wrinkle treatment used by numerous celebrities slows tumour growth by blocking nerve signals that stimulate cancer stem cells.
In laboratory tests, Botox - made from the toxin of botulism bacteria - proved "highly effective" at suppressing gastric cancer in mice.
The promising results have led to the launch of an early clinical trial involving human patients with stomach cancer in Norway.
Locally administered Botox mirrored the effect of "vagotomy" - surgical removal of branches of the gastric vagus nerve, which regulates processes linked to digestion.
US lead researcher Dr Timothy Wang, from Columbia University Medical Centre in New York, said: "Scientists have long observed that human and mouse cancers contain a lot of nerves in and around the tumour cells.
"We wanted to understand more about the role of nerves in the initiation and growth of cancer, by focusing on stomach cancer.
"We found that blocking the nerve signals makes the cancer cells more vulnerable - it removes one of the key factors that regulate their growth."
Botox prevents nerve cells releasing a neurotransmitter - a chemical signal - called acetylcholine. In cosmetic treatments, blocking acetylcholine reduces wrinkles by temporarily paralysing face muscles.
The neurotransmitter is also known to stimulate cell division, hence the link to cancer.
Co-author Professor Duan Chen, from the Norwegian University of Science and Technology, said: "The anti-cancer effects were remarkable, especially with local vagotomy or by injecting Botox.
"It actually surprised us. The finding that Botox was highly effective was particularly exciting."
He added: "We believe this treatment is a good treatment because it can be used locally and it targets the cancer stem cells.
"The Botox can be injected through gastroscopy (a thin tube passed through the mouth to the stomach) and it only requires the patient to stay in the hospital for a few hours."
Botox injections were less toxic than most standard cancer treatments, caused hardly any side effects, and were relatively cheap, said the scientists.
However, they pointed out that combining nerve-targeting treatment with traditional chemotherapy may be the most effective approach.
Tests showed that removing the nerve signals not only had a direct effect, but also made cancer cells more susceptible to chemotherapy drugs.
In mice, the combination of Botox and chemotherapy boosted survival rates by up to 35% compared with chemotherapy alone.
The research, published in the journal Science Translational Medicine, focused on early-stage stomach cancer.
"In the future, we'd really like to look at how we can use this method of targeting nerves to stop the growth of more advanced tumours," said Dr Wang.
His laboratory hopes to develop drugs that block the receptor molecules on the surfaces of tumours that are sensitive to acetylcholine.
This could be more effective than either surgery or Botox in more invasive cancers, since it would seek out cells that have broken away from the main tumour.
Other solid tumours, such as prostate cancer, may have their growth stimulated by similar nerve signals, say the scientists.
But more research was needed to identify the nerves involved, which were expected to vary between different organs and tumour types.