Adding herpes to skin cancer sounds like adding insult to injury, but researchers say that a modified version of the virus that causes cold sores has led to a major breakthrough for cancer patients.

The genetically engineered virus stopped melanoma by "killing cancer cells and sparking the immune system into action," researchers from Britain's Institute of Cancer Research say in a press release.

This is the first time a virus has been used to fight skin cancer, the BBC reports, and although only around a quarter of patients responded to the "T-VEC" treatment, it had impressive results on them, sending 10% of people with aggressive melanoma into complete remission, the Guardian reports.

The lead researcher, professor of biological cancer therapies Kevin Harrington, tells the Guardian that the treatment involves injecting the modified herpes virus into tumors, where it multiplies inside cancer cells until they burst and trigger an immune system response.

"It's like an unmasking of the cancer," he says. "The patient's immune system wakes up and attacks the cancer cells wherever they are in the body." Harrington tells the Washington Post that this is "the farthest along of what we hope will be many more" such "virotherapy" treatments, and he expects the FDA to clear it within a year.

(Click for not-as-great STD-related news.)

This article originally appeared on Newser: Scientists Fight Skin Cancer With Herpes--Successfully

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