WESTPORT, CT (Reuters Health) Sept 28 - Italian researchers have found that expression of simian virus-40 sequences in biopsy specimens from patients with malignant pleural mesothelioma is significantly associated with poor prognosis, particularly in tumors with biphasic or sarcomatous morphology. Their findings are reported in the October issue of Genes, Chromosomes and Cancer.

Dr. Vincenzo Fontana, from "G. D'Annunzio" University, in Chieti, and colleagues explain that several studies have shown that SV40 sequences are present at high frequencies in mesothelioma tissue.

In the present study, the authors analyzed biopsy samples from 83 patients with malignant pleural mesothelioma in order to determine whether SV40 status influenced survival. Nearly 75% of cases had an epithelioid morphology and the remainder had a biphasic or sarcomatous growth pattern.

The researchers found that SV40 negativity was associated with improved survival. When SV40 status was added to histologic subtype, statistical analysis revealed that the hazard ratio for SV40-positive epithelioid mesothelioma patients compared with SV40-negative patients was 1.54. When SV40 positivity was taken into account in biphasic or sarcomatous mesothelioma patients, the hazard ratio increased to 4.25.

In light of their findings, Dr. Fontana's team concludes that "although the pathogenic role of SV40 is still debatable...its presence in mesothelioma may be responsible for a more aggressive clinical outcome." They add that the identification of SV40 as a prognostic cofactor in mesothelioma may lead to novel therapeutic approaches.

The investigators also point out that not all patients were occupationally exposed to asbestos, but they all resided in an area with high risk of environmental exposure. Therefore, it cannot be concluded that SV40-induced mesothelial cell transformation was "an alternative, independent carcinogenic factor."

Genes Chromosomes Cancer 2000;29:173-179.

** POSTED OCTOBER 2, 2000 **