Cancer drugs from hen's eggs?

Scientists at the Roslin Institute, home of Dolly the sheep, hope to use genetically altered cloned chickens in the production of new drugs. The planned project, a joint venture with US biotech firm Viragen, was unveiled at a press conference in Edinburgh last week. The announcement followed earlier media reports that researchers had already created a 'cloned GM (genetically modified) hen' called Britney. But according to Dr Harry Griffin of the Roslin Institute, 'Britney was invented by the Mail on Sunday newspaper'.

If successful, the new technique could result in cheap, novel treatments for diseases such as cancer. Dr Helen Sang, head of the new Avian Project, has already bred genetically altered chickens that produce human proteins in their eggs. But the process is very inefficient, a problem that the researchers hope to overcome by 'cloning' - cell nuclear transfer technology. Human proteins could then be extracted in large quantities from the eggs of a flock of transgenic (genetically-altered) hens.

A spokeswoman for Viragen told New Scientist it was 'highly likely' that the first target would be to produce a human anti-cancer protein to treat melanoma, the most aggressive form of skin cancer. Currently, the only way to produce human proteins in large amounts is by purifying them from genetically altered bacteria - a process that results in milligram quantities of diluted protein, according to Professor Bill Stimson of Viragen. 'Whereas with the egg we are talking about hundreds of milligrams per egg, perhaps up to half a gram' he told the Daily Telegraph newspaper.

Professor Ian Wilmut, head of the team that created Dolly, said it was more important to clone a male equivalent of Britney, which could then be used to breed 'practically endlessly' with hens.