Cancer cells can be destroyed using a colourful combination of chemical ingredients, researchers have discovered.

Using red light, blue dye and a plant hormone, scientists have been able to kill around 99% of cells in laboratory tests.

As all three ingredients have been used in other therapies before, scientists from Cancer Research UK are hopeful it could be used as a cancer treatment in the near future.

Researchers from the Gray Cancer Institute in Middlesex, say the treatment is better than conventional photodynamic therapy which destroys tumours with beams of light, because that relies on a good supply of oxygen, which is not available from cancer cells, to work.

It is a further step in the direction of producing a therapy that directly targets the tumour Sir Paul Nurse Cancer Research UK

The new method uses molecules of indoleacetic acid (IAA), a plant hormone as "fuel" instead.

This means it can get right to the heart of tumours, where oxygen levels are often very low.

'Major challenge'

Scientists treated the cancer cells with a blue dye that becomes chemically "charged" in response to light, along with the plant hormone.

The blue dye absorbs the red light to transfer chemical energy to the plant hormone.

The hormone then shatters to produce free radicals.

These form poisonous by-products which can kill cancer cells.

Professor Peter Wardman, who led the study for Cancer Research UK, said: "Overcoming this oxygen problem is a major challenge in cancer therapy.

"So far we have shown this works with cells in dishes, but because both the dye and the plant hormone are known to be non-toxic in man, we are hopeful that we can quickly translate this treatment into clinical reality."

He told BBC News Online: "So far, we have used cells in petri dishes, although I am confident it's applicable to a wide variety of cancer cells, not just specific types.

He said more research would be carried out with a team from University College London.

Targeting tumours

Sir Paul Nurse, chief executive of Cancer Research UK, says: "This is fascinating work in that it combines using clever technology with something provided by nature � the plant chemicals.

"It is a further step in the direction of producing a therapy that directly targets the tumour."

The research is published in the journal Cancer Research.