January 4, 2006
Cancer Researchers Describe 'Suicide Gene' That Can Halt Metastasis In Some CancersTopics: Medicine
A major problem with cancer is not necessarily the primary tumor formation, but the ability of some tumor cells within that primary tumor to metastasize, or travel to distant sites, where they develop new tumors. Now, a team of cancer researchers from the Moores Cancer Center at the University of California, San Diego (UCSD) Medical Center and St. Jude Children's Research Hospital in Memphis, has shown that a gene commonly lost during neuroblastoma tumor formation, one of the most aggressive cancers in babies and children, is in fact a "metastasis suppressor" gene - Caspase 8.
Caspase 8's normal role is to act as a suicide gene (induces apoptosis) , killing the cell it is housed within in response to cues from the immune system. The research group had previously shown, in normal human cells, that caspase 8 can be activated even without signals from the immune system, particularly when the cell is present in a foreign location. This acts as a mechanism to ensure the cells would survive only in appropriate tissues; for example, liver cells in liver tissue and skin cells in skin tissue.
A number of other cancers may use this same mechanism for regulating their metastatic properties, which the researchers are now studying. Caspase 8 loss or suppression is seen in about 70 percent of small cell lung cancer, about 10 percent of colon cancer and about 35 percent of medulloblastoma. While genetic mutation will sometimes delete both copies of the caspase 8 gene, typically the gene is simply silenced.
Posted by Richard at January 4, 2006 1:55 PM
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