Association Study of Pleural Mesothelioma and Oncogenic Simian Virus 40 in the Crocidolite-Contaminated Area of Dayao County, Yunnan Province, Southwest China.

Background: In Dayao County, Chuxiong Yi Autonomous Prefecture, Yunnan Province, Southwest China, 5% of the surface is scattered with blue asbestos, which has a high incidence of pleural mesothelioma (PMe). Simian virus 40 (SV40) is a small circular double-stranded DNA polyomavirus that can cause malignant transformation of normal cells of various human and animal tissue types and promote tumor growth. In this study, we investigate whether oncogenic SV40 is associated with the occurrence of PMe in the crocidolite-contaminated area of Dayao County, Yunnan Province, Southwest China. Methods: Tumor tissues from 51 patients with PMe (40 of whom had a history of asbestos exposure) and pleural tissues from 12 non-PMe patients (including diseases such as pulmonary maculopathy and pulmonary tuberculosis) were collected. Three pairs of low-contamination risk primers (SVINT, SVfor2, and SVTA1) were used to detect the gene fragment of SV40 large T antigen (T-Ag) by polymerase chain reaction (PCR). The presence of SV40 T-Ag in PMe tumor tissues and PMe cell lines was detected by Western blotting and immunohistochemical staining with SV40-related antibodies (PAb 101 and PAb 416). Results: PCR, Western blotting, and immunohistochemical staining results showed that the Met5A cell line was positive for SV40 and contained the SV40 T-Ag gene and protein. In contrast, the various PMe cell lines NCI-H28, NCI-H2052, and NCI-H2452 were negative for SV40. PCR was negative for all three sets of low-contamination risk primers in 12 non-PMe tissues and 51 PMe tissues. SV40 T-Ag was not detected in 12 non-PMe tissues or 51 PMe tissues by immunohistochemical staining. Conclusion: Our data suggest that the occurrence of PMe in the crocidolite-contaminated area of Yunnan Province may not be related to SV40 infection and that crocidolite exposure may be the main cause of PMe. The Clinical Trial Registration number: 2020-YXLL20.