As a major breakthrough in the treatment of cancer is revealed, Health Editor Barry Nelson talks to the two leading North-East scientists whose research into light therapy could become the next 'magic bullet' to target the disease.

COLIN Self can vividly remember the excitement in Stephen Thompson's voice. He was at a conference in London and he had been asked to ring his colleague and co-researcher, Dr Thompson, back in Newcastle.

Prof Self, who heads the department of clinical biochemistry at Newcastle University, knew Dr Thompson was due to be carrying out tests on laboratory mice.

A lot was resting on the results.

This was the first time that Prof Self's theory that light could be used to enhance the effect of anti-cancer therapeutic antibodies had been tested on live animals. He wouldn't be disappointed.

"The results were so good, Steve rang me up in London. He was so excited about it," recalls Prof Self.

In the experiment - which is due to written up in a scientific journal - mice infected with cancer cells were injected with therapeutic antibodies coated with a light-sensitive substance. When ultraviolet light was shone on the tumours the antibodies close to the cancer cells were switched on.

Within a short time the antibodies, assisted by the animals' own immune system, had killed most of the cancer cells.

"Steve was telling me, overwhelmingly, it worked," says Prof Self.

Evidence that light can be used to enhance the effects of anti-cancer agents was presented to an audience at the Science Media Centre in London yesterday. The Newcastle University team demonstrated that light could be used to "switch on" therapeutic antibodies, stimulating the production of human T-cells, which directly attack "foreign" invaders which cause infection or disease.

They also demonstrated that this same approach can reduce the growth of an aggressive ovarian cancer.

It is still early days, but Prof Self believes that this new approach could dramatically improve the ability of anti-cancer therapeutic antibodies to kill cancer cells. He hopes that early next year human patients can be recruited on to clinical trials to test out the new approach to cancer therapy.

Prof Self has been researching the possibilities of using light to enhance the use of antibodies in cancer treatment since the 1980s.

A Londoner, he took up a post at Newcastle University in 1988 and he has never regretted the move, particularly as he now finds himself at the centre of one of the UK's most fertile cancer drug development centres, home of drugs such as Glivec (leukaemia) and Alimta (mesothelioma).

But it is only recently that he has made the dramatic progress which makes him optimistic about the future and it seems that others share his view.

"I presented some of our findings at an international conference in Kuala Lumpur in Malaysia this summer. There was a gasp from the audience. I had never heard that before," he says.

His colleague, Dr Thompson, another clinical biochemist, became his right-hand man in 1990s. A Geordie who grew up in Fenham, Dr Thompson attended the city's Royal Grammar School and graduated with distinction from the city's university. He is understandably delighted that Newcastle University scientists have made such a potentially significant contribution to fighting cancer.

Prof Self says that billions of dollars have been spent by the major pharmaceutical companies on developing cancer-specific therapies such as Herceptin. These drugs work by latching on to cancer cells and stimulating the patient's own immune system. Unfortunately, many of these laboratory-cultured antibody therapies have a scattergun approach in the body, damaging healthy cells as well as cancerous ones.

"The real challenge is to more accurately target the cancer tumour," says Prof Self. "Less than 20 drugs have been developed like Herceptin. They have been described as "magic bullets", seeking out the cancers, but they are more like cars with no steering wheels. Now we have a steering wheel."

Using light to guide and activate antibodies has fascinated the professor for decades.

"Light is fantastic. It is cheap, it is harmless. By using light with antibodies we can control when it is activated and, more importantly, where it is active."

He believes the technique of cloaking injected antibodies and selectively activating those closest to tumours will greatly improve the success rate of therapeutic antibodies. "We are very excited about this. It opens the door to a tremendous amount of potential."

The first human patients to try out light-activated antibody therapy are expected to be recruited next year. They are likely to be patients with advanced cancers where secondary cancers have appeared on the skin.

"We need to get our light source close to the cancer. If it is on the surface of the skin it will be easy to bathe it with light," Prof Self says.

In the longer term, if the trials confirm the results in mice, it should be possible to deliver ultraviolet light to almost every area of the body, either through endoscopes or via minimally invasive keyhole surgery.

Prof Self believes that prostate cancer, which currently claims the lives of thousands of British men every year, would also present an excellent target for light-activated treatment.

Stafford Scholes, 76, a prostate cancer survivor who set up a support group for other patients in the North Durham area two years ago, says any progress in cancer treatment is to be welcomed but he fears that the long time lapse between developing new therapies and providing them on the NHS could hinder progress.

It is still early days but Prof Self is filled with enthusiasm.

"The important thing is to ensure that this approach is safe. Even aspirin would probably not be licensed now because of the side-effects," he says.

He predicts a rosy future for the use of light in treating cancer.

"Light therapy has got so much going for it. I think you are going to see departments of light therapy being established at major hospitals. There is no doubt about it."