Genetically engineered cell offers possible cancer-killing breakthrough

Research that changes a type of white blood cell so it's a weapon against cancer cells is being hailed by experts as a potential breakthrough in cancer research.

Scientists at the University of Pennsylvania turned T cells into cancer cell killers in a common type of leukemia using genetic engineering. Experts say it may be possible to engineer T cells to kill other types of cancer, including blood, breast and colon, as well.

The research, part of a very small clinical trial involving just three patients who had advanced cases of the chronic lymphocytic leukemia, is published online this week in the New England Journal of Medicine and also in Science Translational Medicine.

Two of the patients have been cancer-free for more than a year, while the other experienced improvements. The plan now, given such promising results, is to expand the trial and treat other patients, then follow them to see long-term effects, the researchers said. They also hope to test it in other, perhaps more aggressive cancers.

"This is a huge accomplishment — huge," Dr. Lee M. Nadler, dean for clinical and translational research at Harvard Medical School, told the Los Angeles Times. Nadler is credited with finding the molecule on cancer cells that the genetically engineered T cells attack.

The researchers said they added instructions to a virus for creating a molecule that binds to leukemia cells and tells the T cells to destroy them. In the clinical trial, they drew blood from the three patients who had chronic lymphocytic leukemia, infected the T cells with the virus and reinjected the blood back into the patients. The engineered T cells multiplied rapidly and killed the cancer cells, then remained for months. "They even produced dormant 'memory' T cells that might spring back to life if the cancer was to return," wrote the Times' Eryn Brown.

A CBS/Associated Press story said the therapy "resulted in armies of serial killer cells that targeted and destroyed cancer cells, even new cancer cells as they emerged. T cells typically attack viruses that way," but it noted study author Dr. Carl June, professor of pathology and laboratory medicine at the University of Pennsylvania, said it's the first time it has been turned against cancer.