Asbestos and SV40 in malignant pleural mesothelioma from a hyperendemic area of north-eastern Italy

Our plain-English summary of Asbestos and SV40 in malignant pleural mesothelioma from a hyperendemic area of north-eastern Italy, by M. Comar, N. Zanotta, G. Pesel, et al (Tumori, 2012).

The study

• Authors: M. Comar, N. Zanotta, G. Pesel, P. Visconti, I. Maestri, R. Rinaldi, S. Crovella, M. Cortale, R. De Zotti, M. Bovenzi
• Journal: Tumori
• Published: 2012;98(2):210-4
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Aims And Background: Malignant mesothelioma is a fatal cancer of increasing incidence in north-eastern Italy. Together with asbestos, the polyomavirus SV40 was hypothesized to contribute to the onset of malignant mesothelioma. To investigate the putative role of SV40 in the individual susceptibility to asbestos-induced malignant mesothelioma, we conducted a molecular epidemiological study on a series of malignant mesothelioma patients from an area in north-eastern Italy hyperendemic for malignant pleural mesothelioma.

Methods And Study Design: We collected 63 mesothelioma samples from incidence cases of patients diagnosed with malignant pleural mesothelioma in the period 2009-2010. DNA was extracted from patients' tissue biopsies using the BioRobot EZ1 Qiagen workstation. SV40 sequence detection and quantification was performed by specific real time PCR. The 74.6% of the 63 enrolled patients had a history of asbestos exposure. The epithelioid histotype was more prevalent in males (64.0%) and the mixed in females (61.5%) who showed significantly higher cancer co-morbidity (46.1% vs 12%, P = 0.005). SV40 was detected in 22% of MM tumors, with a low viral load. In SV40-positive patients, a threefold increased risk of asbestos exposure was observed, more evident in females (OR 4.32) than in males (OR 1.20).

Conclusions: Our findings indicate that a high prevalence of SV40 was present in malignant mesothelioma incident cases from an area hyperendemic for malignant mesothelioma in north-eastern Italy. Although asbestos is considered the main risk factor in malignant mesothelioma onset, a role for SV40 could be hypothesized.

In plain English

This study tested tumors from 63 patients with malignant pleural mesothelioma (50 men, 13 women) diagnosed in 2009-2010 in an area of north-eastern Italy the authors called hyperendemic for mesothelioma. Fresh tumor samples were tested for simian virus 40 (SV40) DNA by real-time PCR. Asbestos exposure histories came from the local mesothelioma registry. Forty-seven of 63 patients (74.6%) had documented asbestos exposure. SV40 DNA was found in 14 of 63 tumors (22.2%), at low levels. None of 45 control samples from women with cervical cancer contained SV40 DNA. Among SV40-positive patients, 82% of men and 100% of women had documented asbestos exposure. After adjustment, SV40-positive patients had about three times the odds of past asbestos exposure of SV40-negative patients, but this was not statistically significant (95% confidence interval 0.54-19.8). The odds ratio was 4.32 in women and 1.20 in men. The authors noted their small sample size. They concluded that if an SV40 and asbestos association among mesothelioma cases were confirmed in larger groups, conclusions about whether the two cause cancer together would depend on exposure among suitable controls.

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 epidemiological study: a case series of mesothelioma patients comparing asbestos exposure between SV40-positive and SV40-negative cases, with a separate negative-control tissue series
• Who was studied: 63 incident cases of malignant pleural mesothelioma diagnosed 2009-2010 in an area of north-eastern Italy: 50 males (mean age 69, range 46-85) and 13 females (mean age 66, range 40-80). Tumors were 37 epithelioid, 22 biphasic-mixed and 4 sarcomatoid. 45 samples from women with HPV-related cervical cancer served as controls.
• Exposure: History of asbestos exposure (fiber types and sources not specified for individual patients), taken from Local Mesothelioma Registry records based on ReNaM guidelines, interviews with work colleagues and occupational insurance data. Tumor tissue was also tested for SV40 DNA (T-antigen sequences) by real-time PCR.
• Main results:
  • 47 of 63 patients (74.6%) had documented asbestos exposure (80.0% of males, 53.8% of females)
  • SV40 DNA was detected in 14 of 63 mesothelioma specimens (22.2%)
  • SV40 detection did not differ by sex: males 11/50 (22%), females 3/13 (23.1%)
  • All 45 control samples from cervical cancer patients tested negative for SV40 DNA
  • Viral load in SV40-positive tumors was low (estimated 6.5 to 9.1% of cells infected)
  • No significant differences between SV40-negative and SV40-positive patients in asbestos exposure, cancer co-morbidity or histotype
  • Among SV40-positive patients, 82% of males and 100% of females (86% overall) had documented past asbestos exposure
  • Adjusted for age, cancer co-morbidity and histotype, SV40-positive patients had about a threefold increased odds of asbestos exposure compared with SV40-negative patients
  • This increase was not statistically significant (95% confidence interval 0.54-19.8)
  • The odds ratio was higher in females (OR 4.32) than in males (OR 1.20); no confidence intervals were given for these
  • Females had significantly higher cancer co-morbidity than males (46.1% vs 12%, P = 0.005)
• The authors' conclusion: The authors concluded that SV40 was frequently present in mesothelioma cases from this hyperendemic area. They added that if an SV40 and asbestos association among mesothelioma cases is confirmed in larger groups, conclusions about co-carcinogenicity will depend on the distribution of exposure among suitable controls.
• Limitations the authors state:
  • Small sample size

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, Pleural Mesothelioma, Malignant Mesothelioma, Mesothelioma, Asbestos Exposure, Epithelioid.

Related studies

• SV40 multiple tissue infection and asbestos exposure in a hyperendemic area for malignant mesothelioma — M. Comar, C. Rizzardi, et al. (2007)
• 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)
• Simian virus 40 transformation, malignant mesothelioma and brain tumors — F. Qi, M. Carbone, et al. (2011)
• 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)
• Evaluation of simian virus-40 as a biological prognostic factor in Egyptian patients with malignant pleural mesothelioma — A.R. Zekri, A.A. Bahnassy, et al. (2007)
• SV40 enhances the risk of malignant mesothelioma among people exposed to asbestos: a molecular epidemiologic case-control study — A. Cristaudo, R. Foddis, et al. (2005)

Browse more research in Tumori, or return to medical research.