Reappraisal of the strong association between simian virus 40 and human malignant mesothelioma of the pleura (Belgium).

Abstract

The frequent association of a monkey oncogenic virus, simian virus 40 (SV40), with pleural mesothelioma and the proposed transmission of the virus from contaminated polio vaccines to humans has received considerable scientific and public attention. We sought to determine whether SV40 would indeed be present in mesothelioma patients from Belgium, as claimed in former studies, and to characterize the viral genome in respective specimens. DNA was extracted from frozen tissue from 12 patients diagnosed with pleural mesothelioma in Belgium. Five different extraction methods were compared and primer pairs targeting four informative regions of the SV40 genome were used to amplify viral products by the polymerase chain reaction (PCR). One of the pairs additionally allows amplification of human polyoma viruses. Southern blotting with an oligonucleotide probe directed at the expected SV40 sequences was also applied. One of the 12 samples contained amplifiable JC virus DNA. In contrast, none of the samples (0/12, 95% CI 0% to 26.5%) was positive for SV40 DNA sequences. The Southern blot analysis confirmed the absence of trace amounts of SV40 PCR product. We also clearly demonstrate that an otherwise specific probe against SV40 could easily hybridize in quite a non-specific manner under recommended conditions. These results provide strong evidence for a lack of association of SV40 with most pleural mesotheliomas in the Belgian population. We recommend a re-examination of other positive case series and avoidance of questionable hybridization practices in future studies.