We're really excited that a common or garden plant hormone could fulfil one of the ultimate aims of cancer research, by providing a drug that only attacks cancer cells and leaves the rest of the body untouched

Professor Peter Wardman, of Mount Vernon Hospital, Middlesex

IAA is normally used by plants to bend their shoots towards the light and helps cuttings to grow roots.

But scientists say a drug based on the molecule, which should be ready for human trials in a few years, also looks to be effective against all tumour types.

They have also found that the hormone can be activated by light. This means that doctors can eradicate accessible tumours by using a dye and then shining a light on it.

In lab tests, this method has already been shown to eradicate 99.9% of cancer cells and will ensure that surgeons remove as much as possible of cancerous tumours.

Professor Peter Wardman, who leads the team from the Gray Cancer Institute at Mount Vernon Hospital, Middlesex, said synthetic drugs based on the plant hormone could save lives.

Professor Wardman said the team had already created synthetic versions of IAA and were looking at ways of making them attack cancer tumours while leaving the rest of the body's tissues unscathed.

Side effects

This could mean an end to side-effects such as hair loss following chemotherapy.

He said: "We're really excited that a common or garden plant hormone could fulfil one of the ultimate aims of cancer research, by providing a drug that only attacks cancer cells and leaves the rest of the body untouched.

"Our work could also open up opportunities for other Campaign researchers, who may be able to exploit the research to develop further ways of targeting tumours."

Scientists test the chemistry of plant extracts

Scientists knew that IAA, which is a member of the auxin family of plant hormones, could in certain circumstances create fragments that produce toxic by-products with the potential to treat disease.

It had previously been studied by scientists in the 1950's as a possible treatment for diabetes, but this is the first time it has been targeted towards cancer.

The researchers believe another plant molecule - derived from horseradish - could be the trigger to turn IAA to fighting cancer.

Horseradish peroxidase has been found to break IAA into smaller fragments, which react in the body to produce powerful toxins.

The scientists hope to target the horseradish molecule to directly attack the tumour cells.

Plant hormones

Professor Gordon McVie, director general of the Cancer Research Campaign, said the research was "incredibly clever".

He said: "It's long been the ambition of cancer researchers to develop drugs that directly target the tumour, and thanks to these amazing plant hormones and a bit of nifty chemistry, we're now a step closer to that ideal.

"It's fascinating that for all the sophisticated technology our scientists are employing, both the active molecules in this study were provided by nature."