In experiments with mice, researchers have found that the body’s immune system can use a surprisingly common molecule to recognize prostate tumors. The molecule comes from a protein found in all cells of the body; however, immune cells appear to respond to it only when it is present on the surface of cells within a tumor. Understanding how this protein, known as histone H4, signals the immune system to respond to malignant cells may help researchers refine immunotherapy strategies that harness the body’s own immune system to fight tumors. Some types of immunotherapy are already being tested in patients, but many questions remain unanswered. In particular, researchers want to know if tumor cells display molecular signposts that tell the immune system, “I’m a cancer cell, destroy me.” Howard Hughes Medical Institute investigator James P. Allison and his team report finding one such signpost in prostate tumors in mice. The finding points toward possible improvements in immunotherapy.
