Virus Suppresses Some Cancers

By Cynthia Kirk

This is the VOA Special English SCIENCE REPORT.

American and British scientists are using genetically changed viruses to seek and destroy cancer cells. A new study shows that a changed cold virus injected into tumors shrinks them with lasting effects when combined with anti-cancer drugs.

The new treatment is showing promise in the treatment of head and neck cancers. Almost five-hundred-thousand people suffer head and neck cancers every year.

Viruses and cancers work by invading tissue cells and taking control of them. Using a process called gene therapy, scientists changed the genes of a virus so that it would target cancer cells. The cancer cells are killed as the virus takes over. However, the virus does not damage normal cells.

The virus used in the study is called ONYX-Zero-One-Five. Researchers developed it to destroy cells that have a changed tumor suppressor gene called P-Fifty-Three. Changes in the P-Fifty-Three tumor suppressor gene are linked to up to seventy-percent of cancerous head and neck tumors.

Scientists report that the combination of the injected changed virus and anti-cancer drugs reduced head and neck tumors in twenty-five of thirty people tested. They said cancerous tumors disappeared in eight people. And they said in other people, the tumors shrank.

The researchers combined the virus treatment with powerful chemicals used in traditional cancer treatment. These chemicals are called chemotherapy drugs

The scientists say that ONYX-Zero-One-Five in combination with chemotherapy is more effective than either treatment alone. They say tumors grew back in earlier studies that did not include both treatments. But, researchers say none of the tumors treated with the combination treatment had grown after six months.

Scientists say the study is one of the most successful yet using gene therapy. They also have begun testing the combination treatment on larger groups of people.

The study involved only people with cancer of the head or neck. Yet the researchers expect the virus treatment to work on other tumors that contain changed P-Fifty-Three genes. And they hope the treatment may be effective against cancers that have spread to other parts of the body.

This VOA Special English SCIENCE REPORT was written by Cynthia Kirk.

Voice of America Special English