There’s hope for treating one of the deadliest forms of cancer. A pancreatic cancer vaccine has proven to be effective in half of patients treated in a small trial, according to a study published in the journal Nature on Wednesday. Pancreatic cancer — often called the “silent killer,” since symptoms don’t show up in most patients until it has spread to other organs — occurs when cells in the pancreas mutate and form a tumor. Memorial Sloan Kettering Cancer Center in New York sent tumor samples from 16 patients to scientists at BioNTech in Germany, the same company Pfizer teamed up with to produce COVID-19 vaccines. After scientists analyzed proteins in patient’s cancer cells, they used messenger RNA — a molecule that contains instructions to direct cells to make a protein — in a vaccine for each patient, attempting to tell the immune system to attack the cancer cells. Along with the vaccine, subjects were also given chemother...