SV40 enhances the risk of malignant mesothelioma among people exposed to asbestos: a molecular epidemiologic case-control study

Our plain-English summary of SV40 enhances the risk of malignant mesothelioma among people exposed to asbestos: a molecular epidemiologic case-control study, by A. Cristaudo, R. Foddis, A. Vivaldi, et al (Cancer Research, 2005).

The study

• Authors: A. Cristaudo, R. Foddis, A. Vivaldi, R. Buselli, V. Gattini, G. Guglielmi, F. Cosentino, F. Ottenga, E. Ciancia, R. Libener, R. Filiberti, M. Neri, P. Betta, M. Tognon, L. Mutti, R. Puntoni
• Journal: Cancer Research
• Published: 2005;65(8):3049-52
• Cited by: 71 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We conducted a case-control study on asbestos exposure and presence of SV40 in tumor samples of malignant mesotheliomas (MMs) and bladder urotheliomas (BUs). PCR analysis revealed the presence of SV40 DNA (SV40+) in eight (42.1%) MMs and 6 (33.3%) BUs. The odds ratio for MM Asb- and SV40+ was 0.4 [95% confidence interval (95% CI), 0.03-4.0], for Asb+ and SV40- was 3.6 (95% CI, 0.6-21.0), and for Asb+ and SV40+ was 12.6 (95% CI, 1.2-133.9). Our results suggest that SV40 increases the risk of MM among individuals exposed to asbestos.

In plain English

This Italian case-control study asked whether the virus SV40, together with asbestos exposure, was linked to malignant mesothelioma. Cases were 19 malignant mesothelioma patients diagnosed at Alessandria Hospital from 2001 to 2004, all diagnosed from pleural specimens. Controls were 18 bladder urothelioma patients diagnosed in Pisa from 2003 to 2004. Asbestos exposure was assessed by interview, and fiber types were not reported. Tumor tissue was tested for SV40 DNA. Asbestos exposure was found in 13 of 19 mesothelioma patients (68.4%) and 4 of 18 controls (22.2%), an odds ratio of 7.6 (95% CI 1.7-33.1). SV40 DNA was found in 42.1% of mesotheliomas and 33.3% of bladder tumors. Compared with patients who had neither factor, the odds ratio was 0.4 (95% CI 0.03-4.0) for SV40 without asbestos, 3.6 (0.6-21.0) for asbestos without SV40, and 12.6 (1.2-133.9) for both. The authors concluded that SV40 alone may not cause mesothelioma but strongly increases the carcinogenic effect of asbestos. They noted the study was limited in size.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Molecular epidemiologic case-control study, retrospective
• Who was studied: 19 malignant mesothelioma patients (cases) diagnosed at the Alessandria Hospital Pathology Unit, 2001 to 2004, diagnosed from pleural effusion or pleural biopsy specimens (16 epithelioid, 2 mixed, 1 sarcomatoid), and 18 bladder urothelioma patients (controls) diagnosed at Santa Chiara Hospital, Pisa, 2003 to 2004; Italy
• Exposure: Asbestos exposure (occupational or environmental, fiber type not specified), classified from interviews using the Italian National Mesothelioma Registry (ReNaM) questionnaire and criteria; and presence of SV40 DNA in tumor tissue detected by PCR. Among exposed mesothelioma patients, 10 had occupational and 3 had environmental exposure from a nearby fibrocement factory; all 4 exposed controls had occupational exposure.
• Main results:
  • Previous asbestos exposure was found in 13 of 19 mesothelioma patients (68.4%)
  • Previous asbestos exposure was found in 4 of 18 bladder urothelioma controls (22.2%)
  • Asbestos exposure was significantly associated with mesothelioma: odds ratio 7.6 (95% CI 1.7-33.1)
  • SV40 regulatory region DNA was found in 42.1% of mesothelioma samples
  • SV40 regulatory region DNA was found in 33.3% of bladder urothelioma (control) samples
  • Compared with no asbestos exposure and no SV40, the odds ratio for mesothelioma with SV40 but no asbestos exposure was 0.4 (95% CI 0.03-4.0)
  • Compared with no asbestos exposure and no SV40, the odds ratio for mesothelioma with asbestos exposure but no SV40 was 3.6 (95% CI 0.6-21.0)
  • Compared with having neither factor, the odds ratio for mesothelioma with both asbestos exposure and SV40 was 12.6 (95% CI 1.2-133.9)
  • Using a second SV40 marker (Tag sequences), the odds ratios followed a similar but smaller pattern, and the association with having both SV40 Tag and asbestos was still positive; these data were not shown
• The authors' conclusion: The authors concluded that their data suggest SV40 alone may not be able to cause mesothelioma in humans, but that it strongly increases the carcinogenic effect of asbestos.
• Limitations the authors state:
  • The study was limited in size
  • The unexpected 33.3% SV40 positivity among controls might have led to an underestimate of the association between SV40 alone and mesothelioma

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: SV40, Mesothelioma, Case-Control Study, Asbestos Exposure, Odds Ratio, confidence interval.

Related studies

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• SV40 multiple tissue infection and asbestos exposure in a hyperendemic area for malignant mesothelioma — M. Comar, C. Rizzardi, et al. (2007)
• The role of SV40 in malignant mesothelioma and other human malignancies — M.A. Pershouse, S. Heivly, et al. (2006)
• Evidence against a role for SV40 infection in human mesotheliomas and high risk of false-positive PCR results owing to presence of SV40 sequences in common laboratory plasmids — F. López-Ríos, P.B. Illei, et al. (2004)
• Simian virus 40 sequences in blood specimens from healthy individuals of Casale Monferrato, an industrial town with a history of asbestos pollution — C. Pancaldi, V. Balatti, et al. (2009)
• Cellular and molecular parameters of mesothelioma — M.E. Ramos-Nino, J.R. Testa, et al. (2006)

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