For the first time, researchers have demonstrated that a human virus can activate proto-oncogenes in infected cells, providing new insights into the way some viruses cause cancer. Proto-oncogenes normally serve as blueprints for proteins that induce proliferation of cells and are thus crucial during development. But if they are turned on later in life, they can trigger the uncontrolled cellular proliferation characteristic of tumors.
Virologist Thomas Albrecht and his colleagues at the University of Texas Medical Branch in Galveston studied human cytomegalovirus, a member of the herpes virus family that has previously been linked not only to cancer but also to arteriosclerosis and birth defects, both of which can involve abnormal cellular proliferation.
They reported in Science last week that infection of cultured human lung cells with the virus turned on three separate proto-oncogenes in the cells during the first two hours after infection, apparently in the process of binding to the cellular membranes. Further studies, they speculated, could lead to a better understanding of how cancer arises.