Before the early 1960s, experimental animals could be immunized against a tumor by removing it after growth, but no immunologic maneuver could cause an existing cancer to disappear.

“and even in experimental animals there was no manipulation that could cause an existing cancer to disappear you could immunize a mouse against a tumor by letting it grow and then removing it and and cause that Mouse to resist an implantation of the same tumor again but once the tumor was growing there was no maneuver that could keep it from growing no immunologic maneuver that could keep it from growing”