Sally O'Neill decided to have a double mastectomy rather than "do a wait-and-see." Richard Knox/NPR hide caption

itoggle caption Richard Knox/NPR

Laura Molina, 9, shows the mask she created expressing the feeling of "sadness." Her mother is being treated for breast cancer at the Lyndon B. Johnson public hospital in Houston. Carrie Feibel/KUHF hide caption

itoggle caption Carrie Feibel/KUHF

Some images of lung cancer are clear cut. But in many others, a nodule on the screen turns out not to be cancer at all. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Vaccines against the HPV virus are already used to prevent cervical and anal cancer. Harry Cabluck/AP hide caption

itoggle caption Harry Cabluck/AP

A 13-year-old girl gets an HPV vaccination from Judith Schaechter, a pediatrician at the University of Miami, in 2011. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images