Increasing evidence for involvement of SV40 in human cancer

Our plain-English summary of Increasing evidence for involvement of SV40 in human cancer, by J.S. Butel (Disease Markers, 2001).

The study

• Author: J.S. Butel
• Journal: Disease Markers
• Published: 2001;17(3):167-72
• Type of article: Review
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

SV40, a small DNA virus, is known to possess strong oncogenic potential. Millions of people were exposed to SV40 as an unknown contaminant of some early poliovaccines. This article briefly summarizes the increasing evidence of the association of SV40 with certain types of human cancer, including mesotheliomas and brain tumors. Unanswered questions pertaining to the pathogenesis of human infections by SV40 and the functional role of the virus in tumor development are noted. It is concluded that SV40 should be considered a candidate human tumor virus and that vigorous efforts to clarify the role of the virus in human disease should be supported.

In plain English

This article was a brief review of published evidence linking SV40, a small DNA virus, to human cancer. SV40 was an unrecognized contaminant of many poliovaccines given to millions of people between 1955 and early 1963. The article reported no new data and did not discuss asbestos. The author noted over 50 published reports of SV40 DNA in human tumors, mainly mesotheliomas, brain tumors and osteosarcomas. According to the review, estimates of how often tumors contained SV40 varied widely but were generally above 50% for mesotheliomas and certain brain tumors and about 35% for bone tumors. The author argued that laboratory contamination could not explain all positive results. The review also described negative findings. Mesotheliomas from Finland and Turkey were found SV40 negative, and several epidemiology studies failed to detect an elevated cancer risk among recipients of potentially contaminated poliovaccines. The author stated that the evidence did not yet prove the virus causes cancer. The author concluded that SV40 should be considered a candidate human cancer virus whose role deserved prompt study.

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: Brief narrative review (synopsis and opinion) by a single author; no original data
• Who was studied: Published studies, not patients studied directly: over 50 reports of SV40 detection in human tumors (mainly mesotheliomas, brain tumors and osteosarcomas) from geographically distinct regions, plus epidemiology studies of poliovaccine recipients
• Exposure: SV40 virus, including exposure through contaminated poliovaccines used from 1955 to early 1963; asbestos and fibers are not discussed
• Main results:
  • Across the studies reviewed, estimated SV40 positivity was generally above 50% for mesotheliomas and certain brain tumors and about 35% for bone tumors, with wide variation
  • In earlier studies cited by the review, microdissected mesothelioma samples had SV40 DNA in tumor cells but not in neighboring non-cancerous cells. The author cited this as evidence against laboratory contamination.
  • The review cited a multi-institutional study in which several laboratories detected SV40 DNA in coded mesothelioma specimens
  • Some studies reviewed were negative. Mesotheliomas from Finland and Turkey and brain tumors from Finland were found SV40 negative, and the author noted that contaminated poliovaccines were not used in those countries.
  • Several epidemiology studies reviewed failed to detect an elevated cancer risk among recipients of potentially contaminated poliovaccines. The author noted it cannot be known which individuals in those cohorts were actually exposed to SV40.
  • The author cited preliminary data from another study suggesting that SV40 is associated with poorer survival in mesothelioma patients
• The authors' conclusion: The author concluded that SV40 should be considered a candidate human cancer virus. The author added that the role the virus may play in causing these tumors remains to be determined.
• Limitations the authors state:
  • The author stated that the evidence does not yet constitute proof that the virus causes these tumors
  • The author stated that the biological role of the virus in these tumors remains undetermined
  • The author acknowledged that it cannot be known whether contamination occurred in any individual positive study

Topics

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

Related studies

• 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)
• Aberrant methylation profile of human malignant mesotheliomas and its relationship to SV40 infection — M. Suzuki, S. Toyooka, et al. (2005)
• The role of SV40 in malignant mesothelioma and other human malignancies — M.A. Pershouse, S. Heivly, et al. (2006)
• SV40: A human pathogen? — R.L. Garcea (2001)
• SV40 multiple tissue infection and asbestos exposure in a hyperendemic area for malignant mesothelioma — M. Comar, C. Rizzardi, 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)

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