The girl whose T cells beat cancer

When Emily Whitehead was six years old, she became the first child ever to receive genetically-modified T cells, an experimental treatment for her leukemia. It cured her, and helped launch the field of cellular medicine. “Sunday Morning” contributor Kelefa Sanneh talks with Emily, and her parents, Kari and Tom Whitehead, about how they defeated her cancer; and with Dr. Siddhartha Mukherjee, a leading cancer specialist and author of the new book, “The Song of the Cell: An Exploration of Medicine and the New Human.”