Pancreatic cancer is incredibly difficult to shake. Even after surgery or chemotherapy, the disease may never go away completely. By some estimates, malignant tumors in the pancreas can recur in up to 80 percent of patients. Those with certain gene mutations appear particularly at risk of the disease returning. A new clinical trial, led by a researcher at the Mayo Clinic, has put a potential vaccine to the test. In a randomized phase 2 trial, nearly every patient who received this vaccine developed an immune response against a mutated gene called KRAS. Mutations in KRAS are found in about 90 percent of pancreatic ductal adenocarcinomas, which is the most common type of pancreatic cancer. If a medicine can target cells that express these mutations, it could theoretically keep the cancer at bay. This does not prove that this vaccine can stop pancreatic cancer from coming back, but these are hopeful signs, especially since other cancer vaccines have shown similar immune responses are linked to improved survival. The findings are published in Nature Medicine. "Historically, pancreatic cancer has been very difficult to treat with immunotherapy," explains first author and medical oncologist Ben George. "What is encouraging is that we were able...