An experimental vaccine aimed at preventing pancreatic cancer before it forms produced a targeted immune response in 18 of 20 people at high inherited risk, according to first-in-human testing of a mutant KRAS vaccine published in Cancer Discovery. Vaccination elicited a significant mutant KRAS-specific T-cell response in 18 of 20 participants, or 90 percent. Over a median follow-up of roughly 16.5 months, no participant developed pancreatic cancer or a high-risk lesion warranting surgery. People with a strong family history of pancreatic cancer or a known germline mutation should not wait for a vaccine. Twenty adults with a hereditary predisposition to pancreatic cancer who also had a pancreatic abnormality identified on imaging, typically a small cyst.