New molecular and epidemiological issues in mesothelioma: Role of SV40

Mesotheliomas are malignant tumors usually associated with occupational asb estos exposure. Simian virus 40 (SV40) is a DNA tumor virus that preferenti ally causes mesotheliomas when injected intracardially and/or intrapleurall y into hamsters. SV40 also transforms human cells in tissue culture, and th ese cells contain extensive DNA damage. In the United States, at least 60% of human mesotheliomas contain and express SV40. In these tumor cells, the SV40 tumor antigen binds and inhibits the cellular tumor suppressors p53 an d Rb. These findings suggest that SV40 may contribute to the development of those human mesotheliomas that occur in people not exposed to asbestos. SV 40 may also facilitate asbestos-mediated carcinogenicity. The epidemiologic al data available are insufficient to address the role that SV40 may have p layed in contributing to the increased incidence of mesothelioma in the sec ond half of this century. (C) 1999 Wiley-Liss, Inc.