Findings could lead to improvements in cancer diagnostics. Cancer researchers led by Antonio Giordano, M.D., Ph.D., associate professor of pathology, anatomy and cell biology at Jefferson Medical College, have for the first time found direct evidence of a potential mechanism of a monkey virus in the development of mesothelioma, a rare connective-tissue cancer commonly associated with asbestos exposure.
In research reported in the August 3 issue of Nature Medicine, Dr. Giordano's team found that simian virus 40 (SV40), a DNA tumor virus from monkeys, targets key proteins that normally prevent tumors from forming, rendering them ineffective. These proteins, made by so-called tumor-suppressor genes, are in the retinoblastoma family (pRb, pRb2/p130, and p107). A viral protein called SV40 T-ag (T-antigen) binds to and inactivates the tumor-halting proteins, causing them to lose their natural ability to regulate cell growth and prevent cancer. The discovery underscores the important role that Rb family proteins play in controlling cell growth.
"We are not saying that the virus is the only factor, but clearly there is more than one factor involved in the onset of mesothelioma," said Dr. Giordano, who is also president of the Sbarro Institute for Cancer Research and Molecular Medicine, which is affiliated with the college. "It is a complex mechanism."
According to Dr.
Giordano, the finding could have important implications for
developing cancer diagnostics, even a "potential test
for the early development of cancer. There are implications
that the pRb2/p130 gene could also be involved in the
development of other cancers, such as ovarian and
Contact: Steven Benowitz
Thomas Jefferson University