How an experimental treatment beat a little girl's cancer

Emily Whitehead has a secret weapon: "My T-cells, part of my immune system, were trained to fight and kill my cancer."

She was only six when she became the first child ever to receive genetically-modified T cells. The experimental treatment cured her leukemia, and the success of her case has allowed all kinds of cellular therapies to be developed. "Kind of made me feel like a superhero or something," she laughed.

She was treated at Children's Hospital of Philadelphia, eventually. But first, Emily had chemotherapy at her local hospital. Chemotherapy cures kids with her kind of leukemia 90% of the time. Emily relapsed, and after a second round, she relapsed again.