Cancer Gene Discovered

California researchers have identified a new genetic mechanism by which cancer can occur. Dr. Ronald M. Evans and his colleagues at the Salk Institute for Biological Studies in La Jolla reported last week in Nature that they had discovered a gene that is able to override the protective effects of anti-cancer genes called anti-oncogenes.

Researchers had previously believed that cancer could occur only when the anti-oncogenes were absent, such as when they are not inherited properly or are destroyed by carcinogenic chemicals or radiation. The new results suggest that cancer can sometimes occur even when the protective genes are present and functioning properly.

The newly discovered gene, called v-erbA, is an aberrant form of the gene for a receptor for thyroid hormone. A receptor is a protein on the surface of a cell to which a hormone must bind to produce its desired effect. When the protein produced by the aberrant gene binds to thyroid hormone, the complex interferes with the normal development of blood cells, leading to the initiation of cancer.