Mesotheliomas are malignancies of the pleural, pericardial, and peritoneal surfaces with a mean survival of less than 1 year from the time of diagnosis (1). While mesotheliomas were extremely rare in the first half of this century, the incidence of these tumors has increased enormously in the last several decades. Presently, 2-3 thousand people in the US develop and die of mesothelioma each year (1). It is estimated that approximately 80% of mesotheliomas develop in people with a history of occupational asbestos exposure or in individuals with family member(s) professionally exposed to asbestos that brought home fibers on their clothing (1). Although conventional wisdom dictates that asbestos is the most commonly associated "environmental" factor with mesothelioma, asbestos does not transform human mesothelioma cells in tissue culture (2). This suggests that additional carcinogens act in concert with asbestos to cause mesothelioma. Recent evidence indicated that Simian Virus 40 (SV40) preferentially causes mesotheliomas in hamsters, and that SV40 is present in up to 80% of human mesotheliomas in the US and in Europe (reviewed in ref. 3 and 4).