No detection of simian virus 40 in malignant mesothelioma in Korea

Our plain-English summary of No detection of simian virus 40 in malignant mesothelioma in Korea, by M. Eom, J. Abdul-Ghafar, S.M. Park, et al (Korean Journal of Pathology, 2013).

The study

• Authors: M. Eom, J. Abdul-Ghafar, S.M. Park, J.H. Han, S.W. Hong, K.Y. Kwon, E.S. Ko, L. Kim, W.S. Kim, S.Y. Ha, K.Y. Lee, C.H. Lee, H.K. Yoon, Y.D. Choi, M.J. Chung, S.H. Jung
• Journal: Korean Journal of Pathology
• Published: 2013;47(2):124-9
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Simian virus 40 (SV40), a polyomavirus, was discovered as a contaminant of a human polio vaccine in the 1960s. It is known that malignant mesothelioma (MM) is associated with SV40, and that the virus works as a cofactor to the carcinogenetic effects of asbestos. However, the reports about the correlation between SV40 and MM have not been consistent. The purpose of this study is to identify SV40 in MM tissue in Korea through detection of SV40 protein and DNA.

Methods: We analyzed 62 cases of available paraffin-blocks enrolled through the Korean Malignant Mesothelioma Surveillance System and performed immunohistochemistry for SV40 protein and real-time polymerase chain reaction (PCR) for SV40 DNA.

Results: Of 62 total cases, 40 had disease involving the pleura (64.5%), and 29 (46.8%) were found to be of the epithelioid subtype. Immunostaining demonstrated that all examined tissues were negative for SV40 protein. Sufficient DNA was extracted for real-time PCR analysis from 36 cases. Quantitative PCR of these samples showed no increase in SV40 transcript compared to the negative controls.

Conclusions: SV40 is not associated with the development of MM in Korea.

In plain English

This laboratory study looked for simian virus 40 (SV40), a monkey virus that once contaminated polio vaccines, in malignant mesothelioma tumors from Korean patients. The authors used 62 wax-embedded tumor samples drawn from 356 cases diagnosed between 2001 and 2009 and held in the Korean Malignant Mesothelioma Surveillance tissue bank. Of the 62 cases, 40 involved the pleura (the lining of the chest). Work history was known for 23 patients. Of these, 11 had jobs the authors considered at risk for asbestos exposure, such as construction, shipbuilding and repair, automobile repair, or farming. The authors tested the tumors for SV40 protein with a staining method and for SV40 DNA with real-time PCR. None of the 62 samples stained positive for SV40 protein. Enough DNA was extracted from 36 samples, and PCR found no SV40 DNA in any of them. The authors concluded that not finding SV40 suggests the virus has no role in the development of mesothelioma in Korea. They noted that their sample may have been too small to detect an association, and that frozen or fresh tissue, which was impractical to obtain, is preferred for this DNA testing.

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: Laboratory study of archived tumor tissue, testing for SV40 protein (immunohistochemistry) and SV40 DNA (real-time PCR)
• Who was studied: 62 paraffin-embedded malignant mesothelioma tumor samples selected from 356 cases diagnosed in 2001 to 2009 in the Korean Malignant Mesothelioma Surveillance tissue bank. The patients were 38 males and 24 females aged 34 to 79 (mean 60.2 years). Tumor sites were pleura 40 (64.5%), peritoneum 21 (33.9%) and pericardium 1 (1.6%).
• Exposure: Simian virus 40 (SV40) protein and DNA in tumor tissue. Asbestos exposure was described only from occupational history, which was available for 23 of 62 patients. Of these, 11 (17.7% of all 62) had jobs placing them at risk for asbestos exposure. No fiber types were reported.
• Main results:
  • Of 62 cases, 40 (64.5%) involved the pleura and 29 (46.8%) were of the epithelioid subtype
  • None of the 62 mesothelioma tissue samples stained positive for SV40 protein
  • In the 36 samples with sufficient DNA, real-time PCR showed no SV40 DNA amplification in any case
  • The mean cycle threshold value for the 36 samples was 34.133 plus or minus 1.440. This was not significantly different from the negative control (34.437 plus or minus 0.160). The positive control was 28.413 plus or minus 0.476.
• The authors' conclusion: The authors concluded that not detecting SV40 in the mesothelioma tissues suggests the virus does not have a role in the development of mesothelioma in Korea. They also stated that their results do not support SV40 acting as a cofactor to asbestos carcinogenicity.
• Limitations the authors state:
  • Frozen or fresh tissue is preferred for PCR detection of viral DNA, but obtaining it was impractical because mesothelioma is infrequent, so paraffin-embedded tissue was used
  • The sample size may not have been large enough to detect an association between SV40 and mesothelioma in Korea

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, SV40, Immunohistochemistry, Pleura, Epithelioid.

Related studies

• Simian virus-40 large-T antigen binds p53 in human mesotheliomas — M. Carbone, P. Rizzo, et al. (1997)
• Human mesothelial cells are unusually susceptible to simian virus 40-mediated transformation and asbestos cocarcinogenicity — M. Bocchetta, I. Di Resta, et al. (2000)
• The retinoblastoma gene family pRb/p105, p107, pRb2/p130 and simian virus-40 large T-antigen in human mesotheliomas — A. De Luca, A. Baldi, et al. (1997)
• Simian virus 40, poliovaccines and human tumors: a review of recent developments — M. Carbone, P. Rizzo, et al. (1997)
• Simian virus 40 large T antigen (SV40LTAg) primer specific DNA amplification in human pleural mesothelioma tissue — C. Pepper, B. Jasani, et al. (1996)
• Progressive aberrant methylation of the RASSF1A gene in simian virus 40 infected human mesothelial cells — S. Toyooka, M. Carbone, et al. (2002)

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