( An important cancer-related gene may pl...)Tumor-suppressor gene is critical for placenta development

Those conclusions come from a new study of the retinoblastoma (Rb) gene in mice. In humans, this gene, when mutated, raises the risk of a rare cancer of the eye called retinoblastoma. Two decades ago, it was identified as the first tumor-suppressor gene, a class of genes that protects cells from becoming cancerous. It has since been shown to be inactivated in many cancers.

In this study, researchers shut off the Rb gene in stem cells that give rise to most of the placenta, resulting in an abnormal placenta and death of the embryos.

The findings provide new insights into development of the placenta and into how the Rb gene blocks tumor growth.

They also raise the possibility that this important tumor-suppressor gene might play a role in miscarriages.

The study, led by researchers at the Ohio State University Comprehensive Cancer Center, is published in the January 2007 issue of the journal Genes and Development.

"Our findings strongly suggest that the Rb gene is important in the development of the placenta, but they have other important implications, as well," says principal investigator Gustavo Leone, assistant professor of molecular virology, immunology and medical genetics and a researcher with Ohio State's Comprehensive Cancer Center and human cancer genetics program.

"People born with one mutated Rb gene have a higher risk of developing retinoblastoma. But are they also predisposed to miscarriage? Do Rb-related defects in the placenta cause learning or physical abnormalities? We are investigating these questions now."

Scientists know that the protein encoded by the Rb gene, the Rb protein, plays an important role in regulating how cells grow. But exactly how it doe
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Source:Ohio State University