Emily Mullin reports via MIT Technology Review: Now two personalized cancer vaccine approaches appear to have safely prevented cancer relapse in a dozen patients with late-stage skin cancer. In recent years, scientists have realized that each patient's tumor harbors a unique set of genetic characteristics, or mutations. So for cancer vaccines to be effective, they'll probably also have to be unique. Two clinical trials, detailed today in separate papers in Nature, are among the first to show that this might be possible. In one trial, eight of 13 melanoma patients who got a personalized cancer vaccine were tumor-free nearly two years after being treated. In a smaller study, four of the six patients who received a vaccine had no detectable cancer for more than two years after treatment. All patients had their tumors surgically removed before getting the vaccine. The customized vaccines are an emerging class of therapies that take advantage of neoantigens, proteins that appear on tumors and seem to be specific to each cancer patient. To make the vaccines, researchers first sequenced DNA and RNA extracted from each patient's tumor. They then used computer algorithms to analyze the mutations on each tumor and predict the best targets that code for neoantigens. Based on that data, they created a personalized vaccine containing up to 20 of these neoantigens. Each patient received several injections of the vaccine over a few months.