At The New York Times' In Theory column, Rachel Nuwer puts forth the hypothesis that viruses can be used to attack tumors. Nuwer speaks to Harvard Medical School's Robert Martuza, Bernard Roizman of the University of Chicago, and New York University's Ian Mohr who tells her that the effect of viruses on cancer cells has been known since the 1990s when doctors noticed that cancer patients who contracted a viral infection often had short reprieves from their cancers. "It was not a coincidence," Nuwer says. "Common viruses sometimes attack tumor cells, researchers discovered. For decades, they tried to harness this phenomenon, to transform it into a cancer treatment. Now, after a long string of failures, they are nearing success with viruses engineered to kill cancer."
Harvard's Martuza notes that there are already several advanced trials for cancer drugs that are made from engineered viruses. A form of vaccinia, the agent that vaccinated against smallpox, is being tested in the treatment of liver cancer, and a herpes virus based on work done by NYU's Mohr is being tested against melanoma. "Unlike chemotherapy, which can diminish in effectiveness over time, oncolytic viruses multiply in the body and gain strength as the infection becomes established," Nuwer says. "In addition to attacking cancer cells directly, some also produce an immune response that targets tumors."