Simian virus 40 (SV40), a polyomavirus, was discovered as a contaminant of a human polio vaccine in the 1960s. It is known that malignant mesothelioma (MM) is associated with SV40, and that the virus works as a cofactor to the carcinogenetic effects of asbestos. However, the reports about the correlation between SV40 and MM have not been consistent. The purpose of this study is to identify SV40 in MM tissue in Korea through detection of SV40 protein and DNA.
We analyzed 62 cases of available paraffin-blocks enrolled through the Korean Malignant Mesothelioma Surveillance System and performed immunohistochemistry for SV40 protein and real-time polymerase chain reaction (PCR) for SV40 DNA.
Of 62 total cases, 40 had disease involving the pleura (64.5%), and 29 (46.8%) were found to be of the epithelioid subtype. Immunostaining demonstrated that all examined tissues were negative for SV40 protein. Sufficient DNA was extracted for real-time PCR analysis from 36 cases. Quantitative PCR of these samples showed no increase in SV40 transcript compared to the negative controls.
SV40 is not associated with the development of MM in Korea.
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Mutations of the epidermal growth factor receptor (
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Primary thymic mucinous adenocarcinoma is an extremely rare aggressive subtype of thymic carcinoma. With a review of literatures, only nine cases have been reported up to present. A 36-year-old woman was admitted for further evaluation and treatment of a mediastinal mass. The patient had no medical history of cancer. The clinicoradiological examination disclosed no tumor elsewhere. After the surgical excision of mediastinal mass, it was grossly a round semi-solid mass with mucin-filled cystic areas. Microscopically solid areas showed cords, small nests and dilated glands infiltrating the fibrotic parenchyma, while the cystic areas were lined by mucinous epithelium with tumor cells floating in extracellular-mucin pools. Some cystic walls underwent malignant transformation of the benign thymic epithelium. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) 7, CK20, CD5, and CDX-2, and negative for thyroid transcription factor-1. In conclusion, the mucinous thymic adenocarcinoma should be recognized as a separate histopathological entity and considered in the differential diagnosis of mediastinal carcinomas.
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