In studies at Beth Israel Deaconess Medical Center and Dana-Farber Cancer Institute in Boston, tumors were eliminated in 25 percent of patients with widespread kidney and lethal skin cancers who received a new cancer vaccine. Another 25 percent showed encouraging shrinkage of large and small tumors. Some of the 75 people who have received the vaccine saw their tumors melt away within weeks and remain gone for two to three years. No toxic side effects, such as those that plague chemotherapy and radiation, have been reported. “If confirmed by larger studies, these results represent an unprecedented advance in the selective and nontoxic treatment of cancers that have spread in the body,” according to Donald Kufe, professor of medicine at Harvard Medical School. The vaccine was developed in his laboratory.