Nota: al virus della leucemia inventato da Gallo, ormai non ci crede più nessuno. Ma persiste la leggenda del virus dell'HIV: troppo pericoloso se la gente sapesse la verità sulle radiazioni...

After years of scientists dismissing the claim, an experiment unveiled yesterday showed that when mice were exposed to radiation the cancer risk in the next generation definitely increased. Dr Brian Lord, of the Paterson Institute in Manchester, who led the research, said: "It shows us how DNA defects can be passed from generation to generation."

His work followed studies into a cluster of leukaemia among children at Sellafield, Cumbria, site of the nuclear plant. It was suggested they ran increased risks of cancer even before birth due to the effect of radiation on the genetic material in their fathers' sperm. Flaws in data collection resulted in the theory being dismissed.

Dr Lord exposed mice to radiation at a level that was too low to cause them any visible damage. Their offspring were outwardly normal, with no increased incidence of leukaemia compared with control groups where the parents had not been irradiated.

But the second generation turned out to have two oddities in their bone marrow, a main source of blood cells. There were signs that cells here had excess DNA damage, while the quantity of cells varied widely from mouse to mouse. These mice were then given a second "hit" of a cancer-inducing substance, said Dr Lord, whose work is published in the British Journal of Cancer.

Some 65 per cent developed leukaemia compared with 38 per cent in the control group. Dr Lord said: "There was no doubt that those groups of animals had a great susceptibility to induction of leukaemia."

Prof Gordon McVie, director general of the Cancer Research Campaign which funded the research, said: "I must emphasise that this is animal data but it would be difficult to see how you could do a human study."

He pointed out that the work supported a well-established theory that it took two "insults" to trigger cancer. he said: "What's intriguing is that this is one of the first demonstrations of a two-hit hypothesis spanning two generations."

Also, the research did not conflict with the well-established theory that the Sellafield workforce introduced cancer-causing viruses to the isolated community. It was possible that radiation could have been the first "hit" while exposure to the virus was the second, suggested Prof McVie.

07 November 1997: Parents' nuclear jobs 'not child cancer risk'
05 May 1997: Virus clue to childhood leukaemia
15 July 1996: Straight line links base to cancer
20 May 1996: Camelford parents use leukaemia helpline
28 March 1996: Sellafield 'did not cause Leukeamia'