A team of researchers has immunized mice with proteins derived from their own cancer cells. The treatment, reported in tomorrow's Science*, dramatically slowed the spread of several types of cancer.
A group of researchers from the University of Connecticut School of Medicine in Farmington made the vaccine by purifying heat shock proteins (HSP), which are released by stressed cells and alert the immune system to destroy them. To test the vaccine's ability to halt the spread of cancer, the researchers injected cancerous lung cells into the footpads of mice. The tumors were removed once they were 5 millimeters wide, and half the mice received weekly doses of heat shock proteins purified from the same type of cancer cells that had been injected. Control mice that were given saline solution all died within 45 days from cancer that had spread from tiny remnants of the tumor. But 80% of the vaccinated mice survived free of cancerous lesions for 250 days. The team had similar success with colon cancer and melanoma.
"We've proved the HSP vaccines can be used as a general strategy to treat a variety of tumors in mice," says Ping Peng, an immunologist with the team. The research is a milestone, says Hans Schreiber, an immunologist and cancer researcher at the University of Chicago. By purifying heat shock proteins from cancers, "you can get individualized therapies," he says. "That is a major breakthrough."