Malignant mesothelioma, a tumor of the pleura, pericardium, and peritoneum,
is presently a worldwide problem. Current therapy is ineffective in slowin
g the course of the disease, and median survival from the time of diagnosis
is rarely greater than 1 year: While the tumor was almost unknown prior to
the second half of the twentieth century, it is presently responsible for
more than 2000 deaths per year in the US alone. Mesothelioma is frequently
associated with exposure to asbestos, but the incidence of cases involving
individuals with low, levels of asbestos exposure is increasing. For this r
eason. there has been much interest in studying whether there are alternati
ve factors that act alone or in conjunction with asbestos in producing this
malignancy. In the last decade, simian virus 40 (SV40) has become the most
notable suspected agent.