The researchers let the cancers blossom. Then they injected the mice with a molecule—an antibody—that was aimed at disrupting any connection that the cancer cells might be trying to make to the CTLA-4. The idea was to see if they could keep the cancer from turning on the brakes of the immune system by disrupting the communication between the cancer and the immune system. “We were just trying things out,” Krummel said. A few days later, Allison came in to check out the progress. “I went, ‘Holy shit! It cured all the mice.’”
