Are Asbestos and SV40 cofactors for mesothelioma?

A Cristaudo, MD, R.Foddis, MD A.Vivaldi, MSc, R.Buselli, MD, V.Gattini, MD, G.Guglielmi, MD, L.Bigdeli, MD, M. Guidi, MD, F.Ottenga, MD

Hospital of S.Chiara, Dep. of Endocrinology and Metabolism, Orthopedic and Occupational Medicine, Pisa Italy

AIM To evaluate the presence of SV40 dna sequences in mesothelioma samples to assess the role of this potential asbestos cofactor in the development of this cancer. METHODS DNA was extracted from formalin-fixed and paraffin-embedded mesothelioma tissue sections; then the PCR analyses were performed and, finally, the samples were blotted and hybridized with an internal oligoprobe. RESULTS At least 72% of all mesothelioma samples tested were positive for a tract of the viral Dna sequence coding for the Large T antigen (LTAg). Since the two other Poliomaviruses, JC and BK, share with SV40 a high grade of sequence homology within the gene coding for LTAg, that result could have been reasonably overestimated. Therefore, we decided to repeat the experiments, increasing the number of samples tested and detecting a sequence within the regulatory region, which is specific for SV40. We found that 55% of all mesotheliomas tested were positive for the regulatory region, while the LTAg-positive samples were 80%. CONCLUSIONS The presence of SV40 in most human mesotheliomas supports the hypothesis that SV40 and asbestos could be co-carcinogens in the development of this tumor. Furthermore, paraffin-embedded tumor specimens were found suitable for SV40 amplification and detection. Despite the biomolecular evidence, there is a surprising lack of conclusive epidemiological studies. An important international follow-up investigation is planned to carry out a multicentric study into this. A large number of mesotheliomas will be analyzed for SV40 Dna sequences and correspondent patients recruited for a case-control study evaluating SV40 association with occupational asbestos exposure.

KEY WORDS: Mesothelioma, asbestos, TAg, Occupational exposure.

For more information, contact

Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Environment and Occupation.