SV40 may be a cofactor in the pathogenesis of some occupational cancers
Department of Endocrinology and Metabolism, Orthopedic and Traumatology, Occupational Medicine, University of Pisa, Pisa, Italy
Aim: From 1995 to date we have investigated the possible role of Simian Virus 40 (SV40) in the etiopathogenesis of mesothelioma and we found that as many as 10 mesotheliomas out of 18 (55%) were positive for specific SV40 DNA sequences. The aim of the present study was to investigate whether SV40 oligonucleotide sequences could be detectable in some classic “occupational cancers” other than mesothelioma: the Intestinal-type Adenocarcinoma of the nose and sinus cavities (ITAC) and the urothelial carcinoma. Methods: Dna prepared from formalin fixed and paraffin embedded ITAC samples were analyzed by means of PCR using primers which allow the amplification of a SV40 specific sequence within the Regulatory Region Dna. Amplificated Dna was blotted following standard Southern blot protocols. Results: The percentage of detection of SV40 DNA sequences was different for the two types of tumor tested. In fact, only 25 % of urothelial cancers resulted positive for specific SV40 DNA sequences. Instead, up to 75% of sinonasal cancers showed positivity for the viral DNA. At present, we did not investigate yet the occupational history of the analized cases. Comments: SV40 is a DNA tumor virus which causes tumors in rodents and transforms many types of cultured cells, including those of human origin. In vivo, SV40 DNA has been detected in several kind of human tumors such as: brain tumors, mesotheliomas, osteosarcomas, Non-Hodgkin's Lymphoma. Interestingly, the rate of viral DNA detection varies within the different tumors. It has been also detected in peripheral blood cells from healthy donors, arising questions about the route of entry and diffusion in humans. It is well established that cancer pathogenesis results from the interaction of multiple factors. Most likely this acquaintance is valid also for those cases with an indisputable history of exposure to occupational carcinogens. Our data suggests that SV40 may act as tumor virus, synergiclly with other carcinogens, in different human tumors occupational cancers included. The difference rate of detection may reflect a different tropism for each organs and also a different role in the multifactorial pathogenesis of these tumors.
Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in poster session 791 (Viral infections).