THE latest source that promises new hope for cancer patients is an African tree. A drug derived from the bark of the African bush willow has been found to hamper blood supply to cancer cells. Tests have shown that it can kill up to 95 per cent of solid turnour cells by cutting off their blood supply.

The new drug, combretastatin, developed by researchers from the Cancer Research Campaign's Gray laboratories at Mount Vernon Hospital, Middlesex, could have wide application. :s more than 90 per cent of cancers are solid turnours or lumps, we are very excited about its potential. It opens the door for the development of other drugs working on the same principle," says Dai Chaplin, who led the research.

Most cancer treatments require high doses of toxic drugs and they take long to kill cancer cells as one centimetre of tumour can contain hundreds of millions of cells. The new drug acts by destroying enclothelial cells lining the blood vessels which supply blood to turnours. By killing one of these enclothelial cells, more than 1,000 tumour cells are killed.