Harmless Virus May Be Deadly to Breast Cancer

A common, harmless human virus can target and kill breast cancer stem cells, Canadian researchers report.

"We suspected that reovirus might be effective against cancer stem cells, because we have shown time and again how well it destroys regular cancer cells," Dr. Patrick Lee, a cancer researcher at Dalhousie Medical School in Halifax, Nova Scotia, said in a news release.

He explained the importance of targeting cancer stem cells.

"Cancer stem cells are essentially mother cells. They continuously produce new cancer cells, aggressively forming tumors even when there are only a few of them," said Lee, who added that cancer stem cells are resistant to chemotherapy and radiation.

"You can kill all the regular cancer cells in a tumor, but as long as there are cancer stem cells present, disease will recur," he said.

Lee noted that he and his colleagues tested reovirus on fresh breast cancer tissue removed from a patient, whereas most cancer studies use cancer cell lines developed for laboratory use. Not only does reovirus kill the cancer stem cells and cancer cells, it also stimulates the body's anti-cancer immune system, the Dalhousie team found.

They're now trying to find a way to harness the immune system to destroy cancer cells while allowing reovirus to freely infect and kill cancer cells.

"Refining this two-pronged approach to killing cancer is our next step. We are taking advantage of the natural characteristics of reovirus and the immune system itself to create a powerful virus-based anti-cancer therapy," Lee said.

The study appears in a recent issue of the journal Molecular Therapy.

More information

The American Cancer Society has more about breast cancer.

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