Sharks may hold cancer key

Sharks may provide a means of attacking cancer that is to be tested for the first time in patients later this year. An extract from shark tissue called squalamine, discovered in the stomach of the dog fish, is thought to prevent tumours from growing by cutting off their blood supply.

It was discovered by researchers working for Magainin Pharmaceuticals, a biotechnology company based in Plymouth Meeting, Pennsylvania, USA. Chairman Jay Moorin told New Scientist magazine: "We were looking for antibiotics in the shark tissue but instead we found a whole family of new compounds that stop cells from dividing."

The compounds are believed to act as a primitive immune system in the shark because they kill infectious microbes. Of the 18 compounds discovered, squalamine showed the most promise as an anti-cancer agent. Other substances have shown potential as treatments for Aids.

Trials of the drug are expected to begin in the autumn in patients with brain or breast cancer, New Scientist said. The idea is to use it to prevent a relapse, rather than as a primary treatment.