Today’s high-tech cancer killers are based on a century-old idea: turning the body’s immune system against tumors. In 1891 a New York City surgeon named William Coley noticed that some cancers seemed to disappear after patients suffered an infection. Acting on a hunch, Coley injected bacteria into a patient with a deadly neck cancer, and the man’s tumor began to shrink.
Now immunotherapy is the hottest field in cancer research. Scientists have learned that an infection can rev up the immune system, dispatching T cells that hunt and kill foreign invaders, including cancer cells.
Research is yielding new ways to boost such immune attacks, including drugs that strip cancer cells of the camouflage they use to hide from T cells. Some approaches take the brakes off the immune system, while others accelerate it or remove molecular and cellular roadblocks in its way, says Elfriede Noessner, a cancer researcher at Munich’s German Research Center for Environmental Health. She has equipped T cells with an extra molecule that strengthens their response to cancer cells and is armed to trigger once it’s inside tumors.
Though not all cancers respond to immunotherapy, researchers are beginning to untangle the genetics that make some tumors vulnerable to immune attack. Eventually, Noessner says, doctors will be able to target more types of cancer with combination treatments, including antibodies that remove immunological barriers. “I think they will be like bacon,” she says. “Bacon is good on everything.”
This story appears in the March 2018 issue of National Geographic magazine.
Lead Image: New kinds of cancer treatments help the immune system’s T cells (pink) find and attack cancer cells (yellow). PHOTOGRAPH BY STEVE GSCHMEISSNER, SCIENCE SOURCE (COLORISED SEM)