Purpose of review: Simian virus 40 is present in some human malignant mesotheliomas. The evidence in favor and against a pathogenic role of simian virus 40 in malignant mesothelioma is discussed in this review.
Recent findings: When simian virus 40 is injected intracardially into hamsters, 60% develop and die of malignant mesothelioma. Moreover, some human malignant mesotheliomas contain and express simian virus 40 DNA and proteins. To date, over 50 laboratories have detected simian virus 40 in malignant mesotheliomas and in other tumors; however, the variability of the percentage of positivity led to a controversy about the role and significance of simian virus 40 in malignant mesotheliomas. Compared with other cell types, human mesothelial cells are unusually susceptible to simian virus 40-induced malignant transformation. The presence of simian virus 40 in malignant mesothelioma has been associated with the activation of specific oncogene pathways. Cocarcinogenesis between simian virus 40 and asbestos in causing malignant mesotheliomas has been demonstrated in three separate research laboratories using different experimental approaches. Epidemiological data possibly linking simian virus 40 and malignant mesothelioma is lacking owing to unattainable identification of infected from noninfected cohorts.
Summary: Available evidence appears sufficient to link simian virus 40 either alone or in conjunction with asbestos in causing malignant mesotheliomas; however, it is still insufficient to speculate about the contribution of simian virus 40 to the overall incidence of malignant mesotheliomas.