From Harvard Magazine:
Cancer is a tough enemy. Against most diseases, the human immune system is a stalwart defender, equipped with a huge arsenal of molecular weapons to fight off bacteria, viruses, and all sorts of other harmful foreign invaders. But cancer flies under the radar: created by the body, it is camouflaged by familiar proteins the system has learned to view as harmless. The relatively new field of cancer immunotherapy seeks to resolve this quandary by retraining the body’s defenses to seek out and destroy cancer cells it would normally pass by. So far, the vaccines and therapies developed using this approach typically involve removing cells from a patient’s body, programming them externally, and then reinjecting them. At that point, the hope is that the cells will travel to the lymph nodes and activate tumor-fighting killer T-cells. “But there are limitations with that protocol,” says Omar Ali, a postdoctoral fellow and a principal collaborator with Mooney. “Specifically, when you inject the cells back into the patient, many of them—which you have spent so much time programming—will die.” Once trained outside their natural environment, Ali says, the cells have trouble readjusting to the body, leaving only 1 to 2 percent to mobilize cancer-fighting T-cells.
Mooney’s team has solved this problem by finding a way to deliver cancer therapy from within. Mooney had been working with biomaterials and implantable systems in his research for years, stimulating blood-vessel growth and bone regeneration using small subcutaneous disks: just the kind of device that might allow researchers to recruit immune cells and activate more efficient attacks on the cancer.