Simian Virus 40 Is Present in Most United States Human Mesotheliomas, but It Is Rarely Present in Non-Hodgkin’s Lymphoma: Conclusion

5 Oct

A high prevalence of virally associated neoplasm has been documented in acquired or congenital immunodeficiency states, specifically Epstein-Barr virus-, human papilloma virus-, and human herpesvirus 8-related tumors. SV40-related lymphomagenesis might, therefore, be more prevalent or easier to detect in such patients. We found a slightly higher percentage of SV40-positive lymphomas in immunocompromised patients than in immunocompetent individuals. Furthermore, specimens from one lympho-proliferative disorder and one AIDS lymphoma were positive with primers for both the RB-pocket binding domain of Tag and the regulatory region. Similar results were obtained in 8 of 12 mesotheliomas and indicate a higher viral load and/or the presence of extensive portions of the SV40 genome. However, the relatively higher prevalence of SV40-positive tumors in immunocompromised patients that we observed in this study may be due to the small sample size tested, and/or to the fact that most of the patients were organ transplant recipients, who have significant blood product exposure and exposure to the donor organ. This hypothesis is supported by recent studies suggesting that HIV-positive individuals do not have a higher frequency of SV40-positive tumors. In these studies, PCR analysis for SV40 sequences in HIV-negative and HIV-positive individuals revealed that SV40 prevalence and load was similar in immunocompromised and nonimmunocompromised patients. Source

Finally, the detection of SV40 DNA sequences in 8 of 12 mesothelioma samples and the detection of the virus in only a small number of lymphomas samples through DNA extractions and PCR reactions that were carried out at the same time by the same investigators rule out the possibilities that either the technical procedure used was not sufficiently sensitive to detect SV40 in lymphomas or that the high percent of positive results obtained with mesotheliomas might be related to PCR contamination.
In conclusion, we find no evidence to support a role for SV40 in the increased incidence of lymphomas in the second half of this century, and we confirm the strong association of SV40 with mesotheliomas.