In 2012, Stephanie Lipscomb became the first human to undergo a new experimental treatment using a genetically engineered version of the poliovirus. The 20-year-old was battling a life-threatening relapse of a brain cancer called glioblastoma. According to the America Brain Tumor Association, such a diagnosis offers a median survival of 14 months, with two-year survival of just 30 percent. 

"The odds weren't good," Lipscomb told USAToday. "They didn't expect me to live more than two years, I don't think."

Three years later, Lipscomb is now cancer-free, a medical triumph more than 30 years in the making by Dr. Matthias Gromeier. The molecular biologist is one of several researchers on the cutting edge of so-called "oncolytic viruses," genetically engineered viruses that target and infect cancer cells. Gromeier used a modified version of the poliovirus, called PVS-RIPO, to force the cancer cells in Lipscomb's tumor to essentially lose their defensive abilities. It's part of an advancing field of cancer immunotherapy that triggers the body's immune system to clear malignant cells.

“All human cancers, they develop ... protective measures that make them invisible to the immune system and this is precisely what we try to reverse with our virus,” Gromeier told "60 Minutes" in a recent profile on the medical breakthrough. “We are actually removing this protective shield ... enabling the immune system to come in and attack.”

A film crew for "60 Minutes" spent 12 months documenting the treatment process at the Preston Robert Tisch Brain Tumor Center at Duke University, where Gromeier and his staff have been working with a small number of terminally-ill brain cancer patients. Eleven of the 22 volunteers for the Phase 1 trial have succumbed to their disease, while two of them are completely cancer-free. The doctors hope that the lessons learned and unexpected successes from the initial trial will convince the FDA to give the treatment "breakthrough status," which would advance Phases II and III and allow for more cancer patients, including children, to take part. 

"The field of immunotherapy is tremendously exciting," Dr. Peter Marks, deputy director for the FDA, told "60 Minutes." "It's been a paradigm shift in how we go about treating cancer. Because there are real products out there that are immunotherapies that are actually helping people to live longer."

So far, some 10 drugs that trigger immune system attacks on cancer cells have been approved for diseases like lung cancer and melanoma. Another half-dozen have promising treatments in development. Stories like the "60 Minutes" piece are sure to increase investment in the area; offering more hope and options for people suffering from cancer. 

"Because PVS-RIPO naturally targets and destroys cancer cells from most common cancer types (pancreas, prostate, lung, colon, and many others), it can be directed against these cancers as well," Gromeier said. "To establish this in the clinic, we plan future clinical trials in patients with cancers other than brain tumors."

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Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Modified polio virus shows promise as 'cancer killer'
Genetic engineering is turning formerly dangerous viruses into beneficial agents that disarm cancer cells and expose them to the body's immune system.