Stacy Erholtz was out of conventional treatment options for blood cancer last June when she underwent an experimental trial at the Mayo Clinic that injected her with enough measles vaccine to inoculate 10 million people.

The 50-year-old Pequot Lakes mother is now part of medical history.

The cancer, which had spread widely through her body, went into complete remission and was undetectable in Erholtz’s body after just one dose of the measles vaccine, which has an uncanny affinity for certain kinds of tumors.

Erholtz was one of just two subjects in the experiment and the only one to achieve complete remission. But the experiment provides the “proof of concept” that a single, massive dose of intravenous viral therapy can kill cancer by overwhelming its natural defenses, according to Dr. Stephen Russell, a professor of molecular medicine who spearheaded the research at Mayo.
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Researchers have known for decades that viruses can be used to destroy cancer. They bind to tumors and use them as hosts to replicate their own genetic material; the cancer cells eventually explode and release the virus. Antiviral vaccines that have been rendered safe can produce the same effects and can also be modified to carry radioactive molecules to help destroy cancer cells without causing widespread damage to healthy cells around the tumors. The body’s immune system then attacks any remaining cancer that carries remnants of the vaccine’s genetic imprint.
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Mayo started out giving patients 1 million infectious units and gradually cranked up the dosage — but it didn’t work until Erholtz and another patient were injected with 100 billion infectious units, he said.

While the treatment worked in Erholtz, whose tumors were primarily in her bone marrow, the results weren’t sustained in the second patient, whose tumors were largely confined to her leg muscles. Russell said researchers need to study how the nature of the tumor affects the lethality of the virus.