Cancer immunotherapy has life-saving powers -- and limits

For some patients, the body’s own natural immune system is being used to fight their cancer. Meet a woman who has lived years past her doctors’ prognosis, thanks to the emerging field of immunotherapy. Then Hari Sreenivasan discusses the promise and limits of the treatment with Matt Richtel of The New York Times and Jeff Bluestone, director of the UCSF Hormone Research Institute.