Immunotherapy, which uses a patient's immune system to treat disease, has increased survival for some adults and children with cancer. However, it has had limited success against many pediatric solid tumors, in part because T cells can become functionally impaired or "exhausted." St. Jude Children's Research Hospital scientists published results in Nature showing that the gene ZMYND8 is a major regulator of CD8+ T-cell exhaustion. The results also showed that removing the gene improves antitumor and antiviral responses on its own and may have a synergistic effect with immunotherapy.