The most startling results centre on mesothelioma, until recently linked primarily to exposure to asbestos. Studies have found that around 70 per cent of mesothelioma cases test positive for the SV40 virus. Over the past 30 years, the number of mesothelioma cases has risen 10-fold, to about 1,000 a year, and is predicted to reach 4,000 early next century. Until now, the increase was blamed on the asbestos industry. But the new findings are leading scientists to suspect that SV40 may account for a substantial number of mesotheliomas.
Some scientists remain sceptical of the link, however.
Robin Weiss, a professor of viral oncology at University College, London, said that SV40 is widely used in laboratories and could easily contaminate tumour samples, fooling the ultra-sensitive tests used to detect the virus. We've looked at mesothelioma and did find it in some cases, but then we got bogged down in whether they were due to contamination or not. However, Dr Bharat Jasani, a leading expert on SV40 and mesotheliomas at the University of Wales College of Medicine, Cardiff, said that new reliability tests rule out contamination as a possible explanation. That part of the story is now over. The time has come where we have to take things more seriously.