Thursday, Sep 28 2000
SV40 sequences in mesothelioma predict poorer survival
Last Updated: 2000-09-27 19:00:46 EDT (Reuters Health) - 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
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."
Chromosomes Cancer 2000;29:173-179.