A potential breakthrough vaccine for pancreatic cancer, the third leading cause of cancer deaths in the U.S., has been hailed as a breakthrough in the decades-long battle against cancer. The results of a test of an experimental vaccine using messenger RNA (mRNA) on 16 patients in New York have shown promising results, with eight of the 16 patients responding to the vaccine and seven remaining patients alive four to six years after surgery. The vaccine is only being tested for patients whose tumors are operable. The discovery could help restore Americans' trust in medical science and potentially make it easier for researchers to develop individualized vaccines that train the patient's immune system.