Australian scientists say an organic compound used by Indian women to paint dots or bindi on their foreheads could hold the key to a breakthrough in cancer treatment. Rose Bengal was first used in the early 1900s as a dye for food, textiles and cosmetics. But now it is proving to be a useful weapon in the fight against skin cancer. From Sydney, Phil Mercer reports.

Television advertisements constantly warn of the dangers of overexposure to the fierce Antipodean sun. Among them is the possible contraction of the disease melanoma, a type of skin cancer characterized by a dark tumor that can spread through the body. More than 1,200 Australians die every year from the disease.

Initial trials of a solution of Rose Bengal injected into some melanoma cells have had a 75 percent success rate in controlling the disease.

Professor John Thompson, the director of the Melanoma Unit at the University of Sydney, says this organic dye could become a powerful cancer-fighting treatment.

"We believe it works by getting into the tumor cells and causing them to self-destruct. But the exact mechanism by which it works is not totally clear. It's not useful for people who have a primary melanoma. The treatment of primary melanoma is surgical excision," he said. "It's useful to inject tumors for people who have recurrences; when the primary treatment has failed and when recurrence in the area, or at more distant sites has occurred."

About 90 percent of Australians who develop melanoma survive thanks to early diagnosis and treatment. If left untreated, however, the disease can be fatal.

Convincing younger people in Australia about the dangers of over-exposure to the sun is a battle campaigners are constantly waging.

Veronica Manock, a 21-year-old student, had two major operations to remove a cancerous tumor from her leg.

"I've had a lot of friends who before this happened to me they just said 'I thought it was just, you know, I'll get a mole cut out and that's it,' whereas I don't think people realize how much danger they're putting themselves into and how easy it is to stop something like this happening to you just from doing little things," said Manock.

Other researchers in Australia are investigating genetic treatments to skin cancer.

There is a pressing need for such research to produce effective treatments. Australians, the majority of whom are fair-skinned, are four times more likely to develop a melanoma than people in Canada, the United States or Great Britain.