An anonymous reader writes "There's an interesting story on CNN about the University of Pennsylvania's human trial results on curing intractable cancer by retraining the patient's own immune system. Quoting: 'Nick Wilkins was diagnosed with leukemia when he was 4 years old, and when the cancer kept bouncing back, impervious to all the different treatments the doctors tried, his father sat him down for a talk. John Wilkins explained to Nick, who was by then 14, that doctors had tried chemotherapy, radiation, even a bone marrow transplant from his sister. ... A few months later, Nick traveled from his home in Virginia to Philadelphia to become a part of the experiment. This new therapy was decidedly different from the treatments he'd received before: Instead of attacking his cancer with poisons like chemotherapy and radiation, the Philadelphia doctors taught Nick's own immune cells to become more adept at killing the cancer. Two months later, he emerged cancer-free. It's been six months since Nick, now 15, received the personalized cell therapy, and doctors still can find no trace of leukemia in his system. ... Twenty-one other young people received the same treatment at The Children's Hospital of Philadelphia, and 18 of them, like Nick, went into complete remission -- one of them has been disease-free for 20 months.'"